Saudi Arabia acknowledged for the first time on Wednesday that 15 of the 19 hijackers in the attacks on the World Trade Center and Pentagon were Saudi citizens.

"The names that we got confirmed that," Interior Minister Prince Nayef said in an interview with The Associated Press. "Their families have been notified."

Previously, Saudi Arabia had said the citizenship of the 15 hijackers was in doubt despite U.S. insistence they were Saudis.

Usama bin Laden — the chief suspect in the Sept. 11 attacks the killed more than 3,000 people — was Saudi born but stripped of his citizenship in 1994.

Asked if he had information on whether bin Laden was dead or alive, Nayef said: "We have no information and we have no interest in this subject."

Nayef also said the kingdom has detained about 30 people since the attacks, based on lists provided by the United States. Some have been released.

Nayef said the men still in detention "have been influenced by bin Laden's thinking."

"It's possible that we will find among them members of the (Al Qaeda) organization," he added. "But so far we haven't found anything."

Nayef said the Saudi leadership was shocked to learn 15 of the hijackers were from Saudi Arabia and said it was natural that the kingdom had not noticed their involvement beforehand.

"How can I place the name of a Saudi on a blacklist when I have nothing to justify the action? The Saudis are free to travel wherever they like."

"If we had known they were going to do what they had done, we would have stopped them," he said.

"I believe they were taken advantage of in the name of religion and regarding certain issues pertaining to the Arab nation, especially the issue of Palestine," said Nayef.

Nayef said the oil-rich kingdown bears no responsibility for the actions of the hijackers.

"This is the truth ... and I defy anyone to prove it," he added.

The prince said there was no evidence so far of Al Qaeda cells operating in Saudi Arabia, but added:

"There may be a limited number of people that we don't know about."

He promised "no mercy" for any Al Qaeda radicals discovered "just as we showed no mercy before Sept. 11."