BEIRUT, JAN. 19 -- Church of England envoy Terry Waite, who was kidnaped one year ago, and other western hostages are now in the hands of Iranian Revolutionary Guards based here, and the Tehran government has banned further involvement by Lebanese groups in the negotiations for their release, according to a senior Shiite militia official.

Waite and some of the 23 other foreign hostages are believed to have beeen seized by pro-Iranian Moslem fundamentalists here. But Shiite sources said the captors were changed three weeks ago after Tehran decided to halt any more meddling in the hostage crisis by local middlemen and armed groups, according to the Moslem militia official.

The official, usually well-informed on Tehran's latest directives to its operatives in Beirut, explained that all future handling of hostage affairs would be carried out between states -- that is, between Iran and the governments of the hostages.

Since the start of the year, most of the captives have been held in the custody of Iranian Revolutionary Guards to prevent Lebanese groups, families or interlocutors from reaching agreements that are not strictly beneficial to Iran, according to Druze and Shiite Moslem militia sources.

In the final week of December, the sources said, Iran stepped in at the last minute and thwarted "The envoy in charge of the negotiations left for Bonn and that was the end of it."

-- a Shiite militia source

chances for a possible release of West German hostage Rudolf Cordes and American journalist Terry Anderson.

A deal had been set to free Cordes in exchange for TWA hijacking suspect Mohammed Ali Hamadei, a ransom of $3 million and proof to the captors that 17 Shiite activists held in Kuwait on bombing charges were still alive and in good health, according to the sources. Anderson, the Beirut bureau chief of The Associated Press, was reportedly next in line to be released, the sources added.

On learning about the deal to free Cordes, Iran contacted its men here and said there would be no deal unless Bonn supplied it with material for manufacturing chemical weapons, arms and other technology. "The envoy in charge of the negotiations left for Bonn and that was the end of it," the militia source said.

Cordes, 53, a representative for the Frankfurt-based Hoechst chemicals company, was abducted by gunmen on the road to Beirut International Airport on Jan. 17 last year, a few days after arriving in Lebanon.

Three days later, Waite, 48, disappeared after leaving his Druze bodyguards outside the offices of a Shiite Lebanese doctor before heading for a meeting with the captors of two Americans.

Druze chieftain Walid Jumblatt said in an interview last weekend that he was still trying to find out whether it was possible to release Waite.

Since his kidnaping one year ago, Waite has been accused by his purported captors to have been working for the U.S. government, despite denials by Washington and by Waite's employer Archbishop of Canterbury Robert Runcie.

To those who remember him at the Riviera Hotel where he stayed, Waite was a strange mixture of a humanitarian and a risk-taker who seemed bound to get into trouble.

"He wanted to show off, taking walks along the Corniche . . . and parading in convoys of cars bristling with guns. He was really saying, 'I am Terry Waite. If you want me, you know where I am, coming and going,' " recalled the manager of a seafront hotel.