West German hostage Rudolf Cordes, held by kidnappers in Lebanon for almost 20 months, was released in Beirut on Monday, informed sources said.

The sources said the 55-year-old Cordes would be handed over to West German officials, possibly in the Syrian capital, later on Monday.Syrian officials in Beirut could not immediately be contacted to confirm his release, but a letter apparently written by Cordes was sent to the Beirut newspaper an-Nahar at dawn on Monday saying he was about to be freed.

The letter, written in German, said: "I should be freed on Monday. Please inform my family."

Cordes, manager for the Hoechst chemicals company in Lebanon, was seized by gunmen on January 17 last year shortly after he flew into Beirut airport.

A clandestine group called "Freedom Strugglers" claimed responsibility.

The group sent an accompanying letter to an-Nahar saying Cordes would be freed within 48 hours and asking for Syrian and West German representatives to go to a hotel on Moslem west Beirut where previous Western hostages had been freed.

The abduction of Cordes was linked to the arrest in West Germany a few days earlier of a Lebanese Shi'ite Moslem wanted in connection with the hijack of a TWA airliner to Beirut in 1985.

The suspect, Mohammed Ali Hamadi, is now on trial in Frankfurt. He was identified by the TWA pilot in court earlier on Monday as the hi-jacker who shot dead an American passenger, Robert Stethem.

Security sources in Lebanon believed Hamadi's brother Abdel Hadi masterminded the abduction of Cordes and another German, Alfred Schmidt, to try to bargain for his freedom.

Schmidt was grabbed four days after Cordes and freed last September. The same "Freedom Strugglers" claimed his kidnap.

The letter from Cordes urged the Bonn government to "do everything taking into account Mohammed."

In Bonn, official sources said earlier on Monday the government was expecting Cordes to be freed in either Beirut or Damascus.