WASHINGTON (AP) - President Bush said yesterday he was "plenty hot" to learn that student visas for two Sept. 11 hijackers were delivered months after they flew planes into the World Trade Center.

He ordered his attorney general to investigate and urged reform of the Immigration and Naturalization Service.

Bush described the matter as "a wake-up call for those who run the INS," but said the agency has antiquated information systems and needs an upgrade. "They got the message and hopefully, they'll reform as quickly as possible," Bush said.

The president said he was "stunned, and not happy" when he learned that no one intercepted the visas for Mohamed Atta and Marwan Al-Shehhi before they arrived at a Florida flight school on Monday.

"Let me put it another way: I was plenty hot," Bush told reporters at a news conference in the White House briefing room.

Before Bush spoke, Attorney General John Ashcroft directed Justice Department Inspector General Glenn Fine to find out why immigration officials failed to pull the notification letters and why there was such a long delay in processing them.

The president ordered Ashcroft, whose department includes the INS, and Homeland Security Director Tom Ridge to investigate and report back to him.

Bush said he was unhappy that the visas remained in the immigration pipeline even though the names on the forms were widely known. He said INS Commissioner James Ziglar was responsible for "this embarrassing disclosure," but should be given a chance to rectify the problem.

"His responsibility is to reform the INS, let's give him time to do so. He hasn't been there that long," Bush said.

Sen. Bob Graham (D-Fla.) chairman of the Senate Intelligence Committee, said he would propose changes in the way the INS issues and monitors student visas. Specifically, Graham called for cross-checking records between police departments, intelligence agencies and Interpol, the global law enforcement arm, "to provide a more complete profile of prospective immigrants."

On Monday, exactly six months after the attacks, Huffman Aviation in Venice, Fla., received student visa approval forms for Atta, 33, and Al-Shehhi, 23. The men were aboard separate hijacked planes that struck the World Trade Center towers, killing thousands.

The pair trained at Huffman in 2000 and early 2001 and sought student visas so they could attend technical schools. The visa for Atta, of Egypt, was approved in July 2001 and a visa for Al-Shehhi, of United Arab Emirates, was approved the following month, said Russ Bergeron, an immigration agency spokesman.

Bergeron described the paperwork the flight school received as a backstop on notification the INS gave the men and the school last summer. He said the INS had no information "regarding these people and their link to terrorism" when the visas were granted.

INS officials assured a Kentucky congressman yesterday that a federal processing center in London, Ky. was not responsible for the delayed paperwork. The agency said Affiliated Computer Services Inc. processed and returned the documents to the INS within the time period stipulated by its contract, said Dan DuBray, spokesman for Rep. Harold Rogers (R-Ky.)

"We were very concerned about the impression that this contractor was given the blame for the agency's process," DuBray said. "The contractor performed the contract the way it was supposed to."

Affiliated Computer Services has a five-year, $75 million contract with the INS to process paperwork involving foreigners visiting the United States. Lesley Pool, the company's chief marketing officer, said the data it processes belong to its clients, and "our role is purely handling the paper."

Rep. Mark Foley (R-Fla.), whose district borders the flight school, said the INS can't blame a lack of funds or equipment.

"How this wasn't discovered by even a rank-and-file worker is beyond my comprehension," Foley said. "Anything with Mohamed Atta's name on it should send alarm bells blasting."