JERUSALEM - An obscure Palestinian group alleged in a tape released yesterday that it was holding BBC correspondent Alan Johnston and demanded as a condition of his release that the British government free a jailed Muslim cleric.

The statement, if confirmed, would be the first public demand made by abductors since Johnston, 44, was seized at gunpoint in Gaza City on March 12. The BBC said the tape showed a picture of his identification card - a possible sign that the contention is true - but not one of Johnston himself.

The recorded statement, by a group called Army of Islam, was provided to, though not broadcast by, the Arabic-language Al-Jazeera television station.

"We demand from Britain that it release our prisoners and particularly Sheikh Abu Qatada the Palestinian, and in this regard we do not forget our prisoners in other infidel countries," the statement said, according to Al-Jazeera's English-language Web site.

Abu Qatada, a Jordanian national of Palestinian origin whose full name is Omar Mahmoud Othman, is a radical cleric held by Britain on suspicion of links to al-Qaeda. He has fought deportation to Jordan, where he was convicted in absentia on terrorism-related offenses.

The Army of Islam surfaced in June, when it was one of three Gaza-based groups that claimed responsibility for the capture of Israeli Cpl. Gilad Shalit during a cross-border raid last year.

The BBC, in a statement posted on its Web site, called for Johnston's immediate release.