The State Department's failure to follow its own rules for issuing visas allowed the Sept. 11 attacks to happen, two top Republicans senators said Wednesday.

Sens. Jon Kyl and Pat Roberts said in a report that "the answer to the question — could 9/11 have been prevented — is yes, if State Department personnel had merely followed the law and not granted non-immigrant visas to 15 of the 19 hijackers in Saudi Arabia."

If laws had been followed, "most of the hijackers would not have been able to obtain visas and 9/11 would not have happened," they said.

There was no comment from the State Department. Responding in the past to similar criticism, State Department officials have said they had no reason to believe the men were terrorists.

Department spokesman Richard Boucher said in October that consular officers followed procedures in place at the time. He said visa procedures have since been improved to identify potential threats.

Roberts, of Kansas, will likely be the Senate Intelligence Committee chairman next year; Kyl, of Arizona, will have a top position in the Senate Republican leadership.

Both were part of the House and Senate intelligence committees' inquiry into intelligence failures leading up to the attacks. Last week, in its final report, the inquiry said agencies were poorly organized and failed to share information, but didn't identify a single intelligence error that, by itself, allowed the attacks to occur.

Kyl and Roberts were among several lawmakers submitting supplemental reports this week. They said the inquiry findings, most of which remain classified, didn't dig deeply enough into the cause of intelligence problems. They said also intelligence committee leaders excluded other lawmakers from key decisions during the investigation.

Their report also said the investigation's scope, confined to intelligence issues, was too limited. The most glaring omission, they said, was the failure to examine State Department procedures for issuing visas.

Kyl and Roberts said the hijackers should have been denied visas as single young men with no visible means of support. But consular officials were uncertain of their authority to deny visas, they said, citing an October report by the General Accounting Office, Congress' auditing arm.

A member of the House panel, Rep. Mike Castle, R-Del., also criticized the State Department in a separate, supplemental report. He said most of the hijackers were wrongly admitted "as a result of decisions made and errors committed by responsible State Department and Justice Department officers."

Immigration matters will be among the issues examined by a new commission investigating the Sept. 11 attacks. The panel will be led by former New Jersey Gov. Thomas Kean.

In their criticism of the inquiry, Kyl and Roberts said they were particularly troubled that its leaders held public hearings despite the objections of some senators.

"The hearings distracted these [intelligence] agencies, our front line troops on the war on terrorism," and "revealed a lot of sensitive information from which our enemies could profit," they said in the report.

Eleanor Hill, the inquiry staff director, denied that sensitive information was released at the hearings, noting that reports and testimonies had been cleared by intelligence agencies.

Of their criticism that rank-and-file members were excluded from important decisions, Hill noted the difficulty of coordinating a complex inquiry examining massive amounts of information — much of it classified — with a panel of 37 lawmakers.

"The members usually realize that investigations aren't run by 15 different people making decisions in different directions," she said in an interview. "You have to have some management of the way the thing is conducted."