Explosive Pickles By MARLISE SIMONS  Published: May 5, 1996

So on March 14, when Belgian customs officials in the port of Antwerp saw an Iranian ship unloading a big cargo container of pickles bound for Germany, they searched it, while the ship proceeded to Hamburg.They expected to find drugs.

What they found instead were three large wooden crates filled with weapon parts. Once assembled, the parts made up what investigators called an unusual weapon "custom-made for terrorism."

Nuclear Trail -- A special report.; A Vast Smuggling Network Feeds Iran's Arms Program

But the airport, which because of its size operates largely beyond the scrutiny of the customs authorities, is believed to be one of dozens of transit points used by the Iranian Government to smuggle, from Europe to Iran, weapons parts and advanced technology used to develop nuclear weapons, Western intelligence officials say.

Some intelligence officials say they believe that despite an embargo imposed by the West, Iran may have a nuclear capacity in as little as five years.

Intelligence officials say the airport is part of an elaborate network set up by Iran's Islamic Government throughout Europe, Russia and the Central Asian republics, one that is apparently also being used to funnel weapons to the Croatian Government and Muslims in Bosnia.

The airport, which is about 35 miles north of Hamburg, is owned by three Iranians who are reputed to be among the biggest arms dealers in Europe, the officials say.

And some German officials say they now suspect that some Iranians who have used the airport for arms trafficking, backed by the Teheran Government, may be implicated in the mysterious death in 1987 in a Geneva hotel room of Uwe Barschel, the former Premier of the German state of Schleswig-Holstein, where the airport is located.

Intelligence agencies are so overwhelmed by the scope of the Iranian smuggling operation that, they said, it is almost impossible to monitor. The clandestine equipment, they said, is often broken down into nearly unidentifiable parts and shipped out from different countries and by different routes.

"It is almost impossible to trace the material being smuggled out by the Iranians," a senior German intelligence official said. "Unless you know exactly what type of technology they are trying to build, the smugglers can collect various parts, from various sources that mask the Iranians' intent.

"The Iranians spread their acquisitions program over a huge area. We were able to stop one recent acquisition only because we obtained the key numbers of the component they wanted to build on a computer disk. Our best hope now is that we can delay the process. We will not be able to stop it."

Iranian officials deny that Teheran is trying to build a nuclear arsenal. Iran's Foreign Minister, Ali Akbar Velayati, has called for all nuclear weapons programs in the Middle East to be disclosed and has chastised Israel for refusing to sign the Nuclear Nonproliferation Treaty, which Iran has signed.

German intelligence officials said they had mounted an ambitious program to halt the flow of arms-related technology to Iran. "There was no way the Germans were ever willing to provide German technology to help the Iranians," Bernd Schmidbauer, the Chancellery Minister in charge of intelligence coordination, said when asked about Iran's smuggling network. "This has been our position and is adhered to strictly."

Intelligence officials said the Iranian effort to acquire nuclear weapons technology mirrors the push by President Saddam Hussein to build a nuclear bomb in Iraq during the last 15 years. The Iranians use many of the old Iraqi smuggling routes and contacts, officials said. But, they added, Iran, unlike Iraq, is able to mask many acquisitions because of its nuclear energy program. The Route A Twisted Path Used by Smugglers

The small airport, tucked in rolling pasture land and with a 2,000-foot runway, would seem to be of little use to the Iranians. It is built for light single and twin-engine aircraft that cannot fly directly to Iran.

But liberal European Community aviation guidelines permit civilian airports to operate free from scrutiny by customs authorities. And planes under 7.5 tons are not required to report flight destinations. These two factors drew the Iranians to the airport almost a decade ago, although the Iranians did not purchase the airport until 1993.

Last August, after two Iranians with close ties to the airport were arrested trying to smuggle heroin and opium into Germany, the Government forbade the planes from leaving the country. But German officials say it has proved almost impossible to enforce the ban.

German companies tied to the airport have bought weapons material and technology for the Iranian Government by falsifying end-user documents for nearly a decade, according to internal company documents. These small European companies, many of which are owned by Iranians, ship material in long, circuitous routes to Iran.

In 1993, with the airport in disrepair and losing money under German management, it was bought by Mehdi Kashani, an Iranian arms dealer, along with Mussa Khayer Habibollahi, a former Deputy Oil Minister of Iran. Mr. Habibollahi, who operated out of London until he disappeared from view a few weeks ago, offered the former owners $8 million for the airport.

The price was twice what the German owners, Heinz-Erich Schreitmuller and Dr. Reinhard Uhlig, a Hamburg dentist, had paid four years before.

The two men agreed to stay on and work for the new management, company records show.

The management of the airport was turned over to an Iranian, Nick Ahmed Semnar. All of the Iranians, wanted for questioning by the German authorities in connection with the airport's operations, are no longer in Germany. Mr. Schreitmuller and Dr. Uhlig are also being investigated by the German authorities for arms trafficking to Iran.

The deal included buying up all the related companies at the airport, including Paratec and Nordflug, which holds the license for the airfield, and Nordair, which holds a license from the German civil aviation authority that allows the Iranians to buy aviation technology from German manufacturers without disclosing the final destination. The Operatives Shadowy Network Of Iranians Abroad

Mr. Kashani, 52, trained as a cleric in Iran, lives in Madrid and was first linked to arms smuggling to Iran in 1983, when a shipment of weapons parts was uncovered leaving Portugal for Iran. Mr. Kashani was involved in the Reagan Administration's efforts to send arms to Iran in return for the release of Western hostages held in Lebanon.

In 1992 he was arrested by the Spanish police for trying to ship 200 Klystron amplifiers, used to help guide missiles, to the Iranian Air Force. Intelligence officials say they believe that he works for Mr. Habibollahi, who is believed to oversee the Iranian Government's clandestine arms acquisitions in Europe.

But despite his record, Mr. Kashani continued to operate in Germany until last year. On Aug. 12 two associates, Parvis Sigurdson, 56, and a man identified in court documents only as Mohammed Ali L., 54, were arrested in the parking lot of the Elysee-Hotel in Hamburg trying to sell about 100 pounds of opium to undercover agents.

The narcotics, the Iranians told the agents, would be delivered through the Hartenholm airport. The Iranians, who were arraigned in a Hamburg court in February, were also trying to buy radar components for American-made F-4 fighter planes for the Iranian Air Force, the authorities said.

Mr. Sigurdson, who worked for Mr. Kashani and who carries a Danish passport, was expelled by the Spanish authorities to Denmark last May, on suspicion of smuggling weapons to Bosnia and Croatia.

The ties between arms smuggling and narcotics trafficking are close.

Money from drug sales is often poured back into illegal arms and technology purchases, intelligence officials say.

Mr. Schreitmuller, in a confidential letter dated Oct. 21, 1993, to his bank, said he had been asked to launder about $72 million of drug money for the Iranian owners of the airport. A German arms dealer, Peter Fisher, wanted for questioning because of what the authorities suspected was an attempt to smuggle radioactive material through Hartenholm to Iran, along with the airport manager, Mr. Semnar, met with Mr. Schreitmuller on Sept. 2, 1993, in a restaurant in Cologne to make the proposal, the letter said. The name of the restaurant was crossed out.

"In the past Mr. Semnar was involved in the transportation of sensitive deliveries to Iran," Mr. Schreitmuller wrote. "He also seems to be involved in international drug trafficking and tried to involve Nordair in Schleswig-Holstein. I rejected these intentions." The Base Route to Iran Starts in Hamburg

Hamburg, a port city of some 1.6 million residents, including 30,000 Iranians, has long been one of the central smuggling points in Europe. Intelligence officials say they believe that the Iranian Embassy in Bonn is the center for Teheran's intelligence operations in Europe.

It is from the embassy, they say, that Iranian agents coordinate plans to acquire illegal weapons and technology, as well as plan the killing of Iranian dissidents. About 60 Iranian dissidents have been killed in Europe and elsewhere since the Islamic Government took power in 1979.

There are many Iranian institutions in Hamburg, including a large Islamic center. The center provides the Iranians, as well as Muslim militants from other countries, with a place to meet and arrange contacts, intelligence officials said. It is also a cover for Iranian agents infiltrated into Europe, they said.

But there are other activities that give the Iranians the cover they need to operate. Iranian ships dock frequently at the port to unload and take on cargo. Every week Iranian truckers make the long drive to Hamburg to deliver carpets and pistachios and return with European goods.

There are three Iranian banks in Hamburg. Iran Air has two direct flights each week to and from Hamburg. And Iranian carpet merchants have built lavish homes and set up some of the finest shops in the city.

Iranians who work at what the authorities consider the fronts for the Teheran Government deny any illegal activity, but they also have little sympathy for Western society.

"If you have a cat and you back the cat into a corner and beat it and abuse it, then the cat will strike back," said a 54-year-old Iranian at the Islamic center, who refused to give his name. "This is what the West is doing to the Muslims of the world. This is why the Muslims fight back." The Violence 2 Deaths Linked To Tiny Airport

There have been at least two unexplained deaths connected to the airport here.

A few years ago Mr. Kashani's wife, Leila Kashani, fell or was pushed to her death from a hotel room in Madrid.

She was frequently listed as a partner in the companies that shipped weapons technology to Iran. In 1984 she and her husband were arrested in Los Angeles for stealing $5 million belonging to a partner in a Swiss engineering company called Tex Consulting and Engineering Inc. The partner was Mr. Habibollahi.

The death of Mr. Barschel, the former Premier of Schleswig-Holstein, on Oct. 11, 1987, in Switzerland shook Germany. Mr. Barschel was found drugged and drowned in a bathtub in the exclusive Beau Rivage Hotel in Geneva. The police have not ruled out suicide, but the case is still under investigation in Switzerland and Germany. Mr. Barschel's widow and brother insist that he was assassinated.

Investigators say there was apparently a meeting in Geneva of Iranian arms dealers and senior Iranian officials that may have included Ahmed Khomeini, the son of Iran's late spiritual leader, Ayatollah Ruhollah Khomeini, and Mehdi Karoubi, the Speaker of the Iranian Parliament, and Rafiq Dust, an arms dealer, hours before Mr. Barschel's body was found.