WASHINGTON — On the eve of the Annapolis summit on the Middle East conflict, the Saudi royal family released 1,500 members of Al Qaeda from prison, requiring them only to promise to refrain from jihad within the Arabian Peninsula.

The presence of the Saudi foreign minister, Saud al-Faisal, at the peace parley has been touted by the White House and the State Department as an important diplomatic breakthrough.

Mr. Faisal has said he was reluctant to attend the meeting, the first time the Saudis would be formal participants in an international peace conference dealing with the Israeli-Palestinian Arab conflict. In an interview with Time magazine, he said he would not shake the Israeli prime minister’s hand and that he was only interested in a response to his kingdom’s peace offer, a full withdrawal from the territory Israel won in 1967 in exchange for peace.

However, while the State Department was wooing the Saudi foreign minister, the kingdom’s Interior Ministry released about 1,500 Al Qaeda members arrested in crackdowns that began in 2003 against the group headed by Osama bin Laden.

The story first broke over the weekend in the Saudi newspaper Al Watan. In an interview with the newspaper, a member of a special committee to reform jihadists in the kingdom, Muhammad al-Nujaimi, said the newly released prisoners had been reformed.

“The committee has met around 5,000 times to offer counseling to 3,200 people, who were accused of embracing the takfir ideology. The committee has successfully completed reforming 1,500 people,” he said.

The ideology of takfir is prevalent in both fundamentalist interpretations of Sunni and Shiite Islam, and it holds that there are separate rules that allow Muslims to kill, lie to, and steal from nonbelievers.

While the Saudi state has at times been targeted by Muslims embracing the philosophy of takfir, its mosques and Ministry of Culture and Information also have been exporting the strain of Islam that encourages this doctrine.

Yesterday, an American intelligence analyst who was following the story said he was wary about the release of the prisoners. “This Saudi process of reform has been so opaque. What no one knows right now is whether the people who have gone through this program have pledged to stop practicing terror or whether they are only pledging to stop terror inside the kingdom.”

Mr. Nujaimi told Al Watan that the reformed prisoners have pledged to end their campaign to rid the Arabian Peninsula of infidels. “After several graded sessions with the committee, and having been convinced of their misguided vision, they renounced their erroneous ideologies, including the concept of driving out all infidels from the Arabian Peninsula,” he said.

The director of the Gulf and Energy program at the Washington Institute for Near East Affairs, Simon Henderson, told the New York Sun yesterday that he did not think the prisoner release was connected to Mr. Faisal’s visit. “I don’t see this as being connected with the Saudi decision to take part in the Annapolis meeting,” he said.

Nonetheless, Mr. Henderson was skeptical about the program. “This would appear to be 1,500 people reformed so far out of 3,200 who have entered the so-called counseling process,” he said. “By my calculation, that is less than a 50% success rate. And what is success? They don’t use violence in the kingdom. Does this mean they can use this elsewhere, for example, in Iraq?”

President Bush yesterday in remarks to foreign ministers and other diplomats attending today’s peace conference in Annapolis, Md., said he was encouraged “by the presence of so many here.” Mr. Bush is scheduled to address the conference today.