Updated

In a reversal, Iran left open the possibility Thursday it may have top Al Qaeda (search) operatives in custody, including the terror network security chief suspected by U.S. officials of planning attacks in Saudi Arabia (search).

Foreign Ministry spokesman Hamid Reza Asefi's comments to The Associated Press contradicted his statement Monday, when he was quoted as telling state-run radio that Al Qaeda members detained in Iran (search) "are not senior members of the group."

Instead, he said Thursday, Iran is unsure of the identities of the Al Qaeda members it has detained and Saif al-Adil may be among them.

"None of the Al Qaeda members in our detention have been identified yet. We do not know whether leaders of the terrorist group, including Saif al-Adil (search), are in Iran or not," Asefi told The Associated Press.

His comments came as investigators worked to determine whether Al Qaeda has been at work in Saudi Arabia, Iran, Morocco and even Iraq.

Officials were seeking any links between the May 12 suicide attacks at housing complexes for foreigners in the Saudi capital, Riyadh, and a string of deadly attacks four days later in Casablanca, Morocco.

"An investigation is ongoing," said Nabil Benabdallah, spokesman for the Moroccan government.

Of the suspected role of Al Qaeda in the Morocco attacks, he said, "We still maintain that there are connections between the Casablanca commando and the international terrorist ring, and we will prove it."

In Saudi Arabia, Interior Minister Prince Nayef announced the arrest of three clerics wanted for supporting Al Qaeda. He said the clerics -- Ali al-Khudair, Ahmad al-Khalidi and Nasser al-Fahd -- were among 11 suspects detained this week in the holy city of Medina.

U.S. officials have said intelligence reports suggest Al Qaeda operatives in Iran had a role in the Riyadh bombings. Saudi Arabia has said it plans to seek the extradition of any Saudis who may be among Al Qaeda members held in Iran.

Iran says it is trying to crack down on Al Qaeda operatives -- especially along its border with Afghanistan, where Usama bin Laden's terror network had a base before the U.S.-led war deposed the Taliban regime.

"For the past 14 months we have vigorously pursued a costly campaign against Al Qaeda by strengthening security of our eastern borders and border areas, arresting, interrogating, expelling, extraditing, prosecuting and jailing suspicious elements infiltrating our territory," Iran's envoy to the United Nations, Javad Zarif, said in a televised interview broadcast Thursday.

"We have done this in far greater numbers than most other countries," he said, speaking from Tehran.

In addition to Al Qaeda security chief al-Adil, U.S. officials have said one of bin Laden's sons, Saad bin Laden; Abu Mohamed al-Masri, an Al Qaeda training chief on the FBI's most-wanted list; and Abu Musab Zarqawi, the operational commander whom Washington accuses of ties to Saddam Hussein, may also be in Iran.