A suspect in the May 12 bombings in Saudi Arabia (search) told interrogators about new plots to hijack planes and use them as weapons, but intelligence officials say he could be lying.

Ali Abd al-Rahman al-Faqasi al-Ghamdi (search), whom U.S. counterterrorism officials describe as a leading Al Qaeda (search) operative in Saudi Arabia, reported the possible hijacking plot, said one intelligence official, speaking on the condition of anonymity.

The man, also known as Abu Bakr al-Azdi, surrendered to Saudi authorities on June 26.

Intelligence officials say they consider his threat credible but do not know if he is telling the truth. Other high-level prisoners are believed to have invented plots for their interrogators in order to create public warnings and cause fright.

But some intercepted terrorist communications are considered as possibly corroborating Abu Bakr's claims, intelligence officials have said.

Abu Bakr is believed to have coordinated the suicide bombings on residential compounds inhabited by Westerners and other foreigners in Riyadh, Saudi Arabia. Thirty-four people, including nine bombers, died in the attacks.

Based on his information, the Homeland Security Department sent a warning to airlines and law enforcement agencies on Saturday. Officials said there was no precise information on when or where such an attack could take place.

A copy of the warning, obtained by The Associated Press, says terrorists may use five-man teams to take over airplanes just after takeoff or before landing and crash them into buildings, as was the case in the Sept. 11 attacks.

The warning suggests an attack could take place by the end of the summer.

"The hijackers may try to calm passengers and make them believe they were on a hostage, not suicide, mission," it says. "The hijackers may attempt to use common items carried by travelers, such as cameras, modified as weapons."

The warning suggests cities on the East Coast and in the Britain, Italy and Australia as possible targets.

"No equipment or operatives are known to have been deployed to conduct the operations," the warning says.