BEIRUT, Lebanon (AP) _ Pro-Iranian kidnappers today freed Jack Mann, a 77-year-old Briton who was the oldest Western hostage in Lebanon, after more than two years in captivity.

Mann was the fourth Westerner to be freed since August. His release appeared to be another step forward in U.N. efforts to arrange a hostages-for- prisoners swap, and came even though Israel has not yielded to the kidnappers' demand to set free more detainees.

A Shiite Muslim leader, Hussein Musawi, said that an American hostage could be released soon.

Prime Minister John Major of Britain said he was ''delighted'' by Mann's release and that he expected him to ''be safely in British hands by 9 o'clock this evening.'' However, Major also told reporters outside 10 Downing Street that he had heard Mann was ''a little unwell.'' He did not elaborate.

A spokesman at 10 Downing Street later said, also without elaboration, ''we are obviously disturbed by'' the reports about Mann's health.

Mann, a former Royal Air Force pilot, was released at 8:40 p.m. at the Beau Rivage hotel in west Beirut, Iran's official Islamic Republic News Agency said in Beirut. The agency said Mann was turned over to the Syrian army.

Mann's release was first reported by a Syrian official who spoke on condition of anonymity to reporters in the Syrian capital. He said Mann was en route to Damascus - the traditional transit point home for freed hostages.

Mann's wife, Sunnie, left Cyprus for Damascus to meet her husband. ''I'm very, very happy,'' she said.

President Bush said, ''I hope it's not the end of the release program. ''There are many more. ... It's so tragic.'' He said the United States could not have normal relations with Iran as long as any hostages are held.

Yossi Olmert, director of the Israeli Government Press Office, said of Mann's release: ''It is, of course, a positive and welcome development. We are happy for the family and for Mr. Mann himself.''

Asked about possible future releases of Arabs held by Israel, Olmert said: ''If more information comes our way, we will reciprocate.''

At least nine Westerners are still missing in Lebanon - five Americans, a Briton, two Germans and an Italian. In addition, Briton Alec Collett was kidnapped in 1985, and British officials say he is assumed dead following claims he was killed in 1986 in retaliation for British complicity in U.S. bombing raids on Libya.

Most of the hostages are believed held by Shiite factions linked to the Iranian-allied Hezbollah.

Mann was held by the Revolutionary Justice Organization, a Shiite Muslim faction that also holds American hostage Joseph Cicippio.

In Norristown, Pa., Thomas Cicippio, Joseph's brother, said he was ''very excited that a hostage has been released.''

''It gives me a lot of hope,'' he told The Associated Press. ''Things look a lot more positive right now. I feel as though it may just be a matter of time until they release Joseph and perhaps all the hostages.''

John McCarthy of Britain, who was released from captivity on Aug. 8 after more than five years in Lebanon, said he was ''absolutely delighted.''

''My thoughts are with him and his wife Sunnie as they start their life together again,'' McCarthy said of the Manns. ''It is my greatest hope that they will have plenty of quiet time to get to know one another and will not face any pressure to live the present or relive the past in the public eye.''

Revolutionary Justice had said last week it would not free another hostage because Israel had reneged on a promise to free 20 additional detainees.

Israel released 51 Arab prisoners on Sept. 11 in what it said was a goodwill gesture aimed at freeing hostages. Although the Jewish state has not released any prisoners since then, it was possible the kidnappers obtained assurances in secret talks.

Mann, a former World War II squadron leader, was kidnapped while going to the bank on May 12, 1989. During his captivity, he was once reported to have died - a report his wife initially said she believed but later discounted.

Revolutionary Justice issued two statements earlier today saying Mann would be freed. Each was accompanied by the same photograph of Cicippio.

One statement said the group decided to free Mann because of the ''immense efforts'' by U.N. Secretary-General Javier Perez de Cuellar, who has been trying to arrange a swap of hostages, Arabs held by Israel and Israeli soldiers missing in Lebanon.

Revolutionary Justice also said Mann's release would be ''the prelude for the next stage to speed up the closure of the file of the prisoners and the hostages.''

Also today, the Iranian news agency quoted Iranian Deputy Foreign Minister Ali Mohammad Besharati as saying: ''By January, all hostages irrespective of their nationalities will be able to go home.''

Musawi, a leader of the pro-Iranian Hezbollah, which is believed to be the umbrella group for hostage-holding factions, told reporters: ''If things continued to proceed normally, an American hostage will be released. Maybe within a week or less than a month.''

He said Mann's release was intended ''to facilitate Perez de Cuellar's mission. The other side is required to facilitate his mission too.''

He apparently referred to the kidnappers' demands that Israel release more Arab prisoners, or possibly Sheik Abdul-Karim Obeid, the Hezbollah leader who was taken from his home in south Lebanon by Israeli commandos in 1989.

The Tehran Times, meanwhile, said in a report scheduled for publication Wednesday: ''Two (hostages), one British and one American, will be released this week.'' The newspaper said one captive ''may be released within hours and the second later in the week, possibly during the weekend.''

The Tehran newspaper is believed to reflect the views of Iranian President Hashemi Rafsanjani, who apparently hopes helping to end the hostage ordeal will improve Iran's image and pave the way for Western economic ties.

On Sept. 11, after receiving definite word one of its missing soldiers was dead, Israel freed the 51 Arab prisoners. The next day, Revolutionary Justice issued a photograph of Mann and said he was well.

Then, on Sept. 13, the body of a missing Israel soldier was returned to the Jewish state - leaving five Israeli servicemen unaccounted for. But in the ensuing days, Shiite clerics differed over whether Israel had done enough to warrant freeing another Westerner.

The longest-held hostage in Lebanon is American Terry Anderson, chief Middle East correspondent for The Associated Press. He was kidnapped March 16, 1985.