GAZA CITY, Gaza Strip - An al Qaeda-linked website posted a recording from the purported kidnappers of a BBC correspondent Wednesday -- along with the reporter's press card -- in sign of possible involvement by the terrorist network.

Palestinian security officials said they believed the group claiming to hold Alan Johnston -- the Army of Islam -- may have had foreign help, but stopped short of naming al Qaeda. It remained unclear whether the shadowy Palestinian group already has ties with al Qaeda or was merely trying to attract its support.

Johnston, 44, was kidnapped March 12 in Gaza City by Palestinian gunmen. He has not been heard from since, and the recording was the first public statement from a group claiming to be holding him.

The fiery, 20-minute recording from the Army of Islam demanded that the British government "release our prisoners and particularly Sheik Abu Qatada, the Palestinian" in exchange for Johnston. Abu Qatada, a Jordanian of Palestinian origin, is accused of terrorist links and is awaiting deportation to Jordan from Britain.

A picture of Johnston's BBC press card accompanied the recording -- the strongest evidence yet that the group is holding the journalist.

The message did not include any signs of life from Johnston, nor did it mention Israel or its occupation of Palestinian territories.

"We will not sit idly watching our Muslim brothers being tortured with the worse torture inside the infidels' prisons. Thus we have managed to take the Briton Alan Johnston as a prisoner," a voice in the recording said.

The recording has generated some optimism that Johnston is still alive.

"We profoundly hope that today's news may be a sign that Alan will soon be safely released," said the BBC's deputy director general, Mark Byford.

A spokeswoman for the British Foreign Office said the government wanted to review the tape before commenting on it.

"A video such as this is very distressing to Alan's family, friends and colleagues. We are of course in constant contact with his family and the BBC. We are looking into this as a matter of urgency, in particular we are continuing to work closely with the Palestinian Authority in order to establish the facts and to try and secure Alan's safe release," the spokeswoman said on condition of anonymity in line with government policy.

The recording was posted on a Web site often used by al Qaeda and its Iraqi branch to post messages. Palestinian militants rarely use the site.

The Army of Islam also claims it participated in capturing Israeli soldier Cpl. Gilad Shalit in a June 2006 cross-border raid. The group is headed by a powerful Gaza clan, the Doghmushes, widely believed responsible for several kidnappings of foreigners in Gaza. Up to now the clan's activities have been described by Palestinian officials as largely criminal.

The recording showed clear al Qaeda elements: its posting on a website, its demands for the release of other suspected al Qaeda militants, and its threats to kidnap more infidels -- a byword for non-Muslims and Westerners.

One Palestinian official, speaking on condition of anonymity because of the sensitivity of the matter, said he believes the recording is a sign that the kidnappers have al Qaeda contacts. However, other Palestinian officials believed the group was using the tape to market itself to potential al Qaeda funders and raise its profile among Muslim extremists.

Islamic extremism has taken root in Gaza, though the extent of al Qaeda's presence is unclear.

This week, members of a fundamentalist Islamic group lobbed a bomb that killed a man during a fight with security men at a U.N. school in Gaza. They were protesting a school festival that included traditional Palestinian dancing.

A previously unknown group, the "Swords of Islam," has bombed Internet cafes and other outlets it complained were turning youths away from prayer and fighting Israel.

The Gaza Strip's established militant Muslim group, Hamas, has condemned the violence but has said it is unable to stop it.

The poverty that helps lead to extremism has been exacerbated by an international aid boycott imposed on March 2006, when a Hamas-led government took office following its parliamentary election victory.

The embargo was imposed after Hamas rejected international demands to recognize Israel, renounce violence and accept past peace accords.