Palestinian Authority officials on Wednesday expressed doubts as to the authenticity of an announcement by an Islamic group in the Gaza Strip according to which it is holding BBC correspondent Alan Johnston. "We have serious doubts regarding this report's authenticity," said PA Information Minister Mustafa Barghouti. "The Palestinian government is making efforts to solve this case. I don't rule out the possibility that this new announcement is intended to hamper our efforts." The recording, which includes audio and photographs, shows a large picture of Johnston's BBC press card - the strongest evidence yet that the Army of Islam is actually holding the journalist. However, the tape did not include any signs of life from Johnston himself, such as footage or recordings of his voice. The recording was posted on a Web site often used by al-Qaida and its branch in Iraq to post messages. Other terrorist groups also have used the site, though it is rarely used by Palestinian organizations. The 20-minute recording includes a fiery diatribe against the West, posting a slideshow that includes images from the war in Iraq, Muslim prisoners at Guantanamo Bay, and Western soldiers praying before a cross. Islamic music plays in the background, and pictures glorifying Sheikh Abu Qatada, a militant Islamic cleric being held in the UK, are repeatedly shown. In the recording, the Army of Islam demanded the British government "release our prisoners and particularly Sheikh Abu Qatada the Palestinian" in exchange for Johnston. A copy of the recording also was left at the Gaza City office of the al-Jazeera satellite channel, though it did not broadcast the tape. Hamas expressed relief that another party had claimed responsibility for the abduction of Johnston. "The announcement by a group calling itself the Army of Islam has left no room for speculation as to the identity of the kidnappers," said Ayman Taha, a Hamas spokesman in the Gaza Strip. "Now that the picture is clear, we hope this will have a positive impact on efforts to secure the release of the British journalist. The kidnapping of foreigners is against Islamic tradition and laws and causes damage to our cause." The Hamas spokesman criticized the announcement by the Army of Islam, saying such groups have distorted the image of Islam. PA security officials told The Jerusalem Post that they had no idea who was behind the group, which first appeared in the Gaza Strip about a year ago. "We first heard of this group when it issued a joint statement with Izaddin Kassam [Hamas's armed wing] and the Popular Resistance Committees taking credit for the kidnapping of Israeli soldier Gilad Schalit," the officials said. But Taha said his movement had severed its ties with the Army of Islam "after discovering that the group was moving toward accusing other Muslims of being non-believers." Asked if he was aware of allegations that the group was linked to al-Qaida, Taha said: "We don't know if they went to al-Qaida after we cut off our relations with them." Another Hamas representative expressed deep concern over the emergence of al-Qaida-affiliated groups in the Gaza Strip over the past two years. "The presence of these groups on the Palestinian arena is not good for us," he said. "Their demands and agenda are often unlinked to the Palestinian cause." According to the Hamas official, the Army of Islam is one of three al-Qaida-linked groups now operating in the Gaza Strip. The other two are the Righteous Swords of Islam and the Salafi Movement. "These are very dangerous groups that are receiving funds and weapons from al-Qaida and other radical Islamic organizations abroad," he added. "We are talking about several thousand young men who have been recruited to these groups in the past year. Many of the new soldiers used to belong to Hamas and Islamic Jihad." Commenting on the latest developments surrounding the case of Johnston, a senior PA official in Ramallah said: "If the reports about the presence of al-Qaida in the Palestinian territories are true, then we are headed toward civil war as in Iraq," he said. Johnston, 44, was kidnapped on March 12 in Gaza City and has not been seen or heard from since. There were claims by a previously unknown group that he was killed, but no proof was ever provided. BBC Deputy Director-General Mark Byford said that the BBC remained deeply concerned for Johnston's safety. "Fifty-nine days after he was abducted, our sole concern is for Alan's welfare, and for that of his family. What we and they want more than anything else is Alan's safe return," he said. A spokeswoman for the British Foreign Office said the government wanted to review the tape before commenting on its contents. "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. AP contributed to this report.