The FBI is investigating whether a charitable contribution made by the wife of the Saudi Arabian ambassador to the United States may have indirectly benefited two of the Sept. 11 hijackers, officials said yesterday.

Saudi officials acknowledged yesterday that Princess Haifa al-Faisal, the wife of Saudi Ambassador Prince Bandar bin Sultan, gave money to the family of Osama Bassnan, a Saudi citizen, when they were in the United States. One of Bassnan's friends, Omar al-Bayoumi, helped two of the Sept. 11 hijackers, Khalid Almihdhar and Nawaf Alhazmi, with introductions to the Muslim community when they arrived in San Diego in 2000. Al-Bayoumi hosted a party and helped Almihdhar and Alhazmi with rent payments.

But Saudi officials said the money was donated to help defray the cost of medical treatments for the Bassnan family. It was one of many charitable contributions that the princess, daughter of the late Saudi King Faisal, makes regularly to Saudis who need money in the United States, they said. There is no evidence any of the money made it into the hands of the hijackers, the officials said.

The possible link comes just as the United States is trying to line up Saudi Arabia's help for a likely confrontation with Iraq. Relations between the two countries have been delicate since the Sept. 11, 2001, attacks. Fifteen of the 19 hijackers were Saudis, and questions have arisen about whether Saudi government officials or private foundations may have helped fund terrorists and may still be doing so.

"All of this raises alarms," one senior administration official said.

The use of Saudi air bases was critical to the swift U.S. victory in the Persian Gulf War, and President Bush will need to use them again if he leads an attack on Iraq, which shares most of Saudi Arabia's northern border. Officials of the oil-rich kingdom have made no such commitment this time and have sent contradictory signals about their intentions.

A Saudi Embassy official said yesterday that the princess provided $15,000 in 1998 to Bassnan and followed up with $2,000 monthly checks to Bassnan's wife, Majida Ibrahim Ahmad, while she was living in Falls Church and Baltimore. Bassnan was deported to Saudi Arabia Nov. 17 and his wife was deported to her native Jordan the same day, both on visa violations, officials said.

The checks were issued from the princess's account at Riggs Bank in Washington. The Saudi Embassy called the president of Riggs Friday night after learning of the FBI investigation from media inquiries.

Bank officials opened the bank so embassy employees could spend the night going through the checks that had been issued from her account. Officials were still going through the records to see if any checks sent to the Bassnan family were endorsed over to Bayoumi. Some of the checks, officials said, were endorsed over to third parties -- perhaps members of the Bassnan family.

A congressional panel investigating the Sept. 11 attacks took note of the payments from the princess while reviewing FBI files, sources said. Panel members were not satisfied the bureau had fully examined the money trail there and asked the bureau for more information.

The bureau and the Justice Department had firmly resisted the committee's request to declassify the information. They now say they cannot comment because it is a matter of continuing investigation.

Saudi Arabia's willingness to cooperate in Washington's war on terrorism has been sporadic, and hostility toward the United States runs high on the kingdom's streets. But administration officials said they recently have seen hopeful signs. The officials said the Saudi government has aided efforts to prevent the export of money to terrorists, often through charitable front groups. But the officials said Saudi Arabia still needs to do a lot more and remains a worrisome source of financing for terrorists.

Russian President Vladimir Putin raised an uncomfortable subject for Bush by publicly questioning Saudi Arabia's commitment to fighting terrorism at the presidents' joint appearance Friday. Putin said "we should not forget" that Saudi Arabia was the home country of 15 of the 19 hijackers.

White House officials learned about the FBI investigation from reporters' inquiries on Friday. Newsweek first reported the FBI's interest in the princess's checks on its Web site late that evening. Bush and national security adviser Condoleezza Rice returned to Washington last night after a five-day European tour, and officials said the administration will decide this week whether to take up the matter with the Saudi government.

Some administration officials held out hope that the payments had some innocent explanation, such as a family relationship or friendship. "There are any number of legitimate reasons it could have happened," an administration official said. "We just don't know yet."

Staff writer Dana Priest contributed to this report.