Syrian forces have sealed off an area in southern Beirut in which they believe 15 Western hostages, including at least one American, are being held, Britain's Independent newspaper said on Wednesday.

The report quoted Syrian intelligence officers as saying the hostages were being held by members of the Iranian-backed Hezbollah (Party of God) militia in an area no bigger than 1,000 yards square inside the Hay Madi Barracks.The newspaper said the evidence had come from members of the Syrian-backed Amal militia gained during its recent fighting with Hezbollah and from tip-offs and observation.

It quoted the security men as saying there was no prospect of freeing the hostages by force. Further negotiations, they said, were required with Hezbollah.

"Security men said it would be impossible to storm the barracks with any hope of success," the newspaper said. "They estimated there were 250 guards in the building with many more in the surrounding areas. Amal officers said there were at least 400 Iranian Revolutionary Guards in the southern suburbs."

The Syrian officers said that though Syrian control of the area was not watertight it was certain neither the kidnappers nor their prisoners could be moved and that pressure on the barracks would make negotiations easier.

The newspaper quoted the Syrian officers as saying U.S. hostage Col. William Higgins had been moved to the barracks before the Syrians entered south Beirut last month.

Higgins, commander of Observer Group Lebanon (OGL) of the U.N. Truce Supervision Organization, was seized last February by three gunmen who intercepted his car south of Tyre. Responsibility was claimed by a group calling itself the Organization of the Oppressed of the World.

The newspaper made no specific reference to any of the other hostages as being held in the barracks.

Four British parliamentarians who have met senior Iranian officials in Tehran with the aim of improving ties were expected to return to London on Wednesday and brief the Archbishop of Canterbury, Robert Runcie, who arranged the visit.

The four, from several parties, were on a Church of England mission that sought to find common ground with Iran that might lead to the release of Britons held in Beirut.

A senior Iranian official said Iran would try to help find the Britons if Britain took steps toward helping free Iranian captives in Lebanon.

The Iranian news agency IRNA, monitored in London, said the pledge was made in Tehran on Tuesday by Prime Minister Hussein Musavi's deputy, Alireza Moayyeri, during a meeting with the visiting members of parliament.