Senior U.S. intelligence officials have concluded that the risk of a terrorist attack on U.S. soil has increased significantly in recent weeks, but policymakers disagree deeply about whether to issue a general warning to the public about the danger, sources familiar with the debate said.

The FBI, CIA and other intelligence agencies have documented a rise in intelligence information over the past two weeks indicating an increased possibility of attacks. As a result, the FBI is planning to warn law enforcement agencies by today that there is a heightened danger of attack on apartment buildings, hotels and other "soft targets," said sources who have seen draft copies of the bulletin.

A similarly wary assessment of heightened risk was issued by the CIA last week and circulated among senior U.S. intelligence officials, sources said. The warning also comes as FBI officials prepare to submit a classified report to Congress next week that concludes that the al Qaeda terrorist network remains the most significant threat to domestic security, sources said.

But administration officials are divided on the significance of the surge in threats reported by detainees or obtained by intelligence methods and have been unable to reach agreement on how to respond, knowledgeable sources said.

Many intelligence analysts in the Pentagon and White House believe that the surge in activity is cause for serious alarm, especially because the prospect of war with Iraq heightens the risk of attacks by Iraqi agents, al Qaeda operatives or others eager to take advantage of the political climate. Many of these officials favor issuing a general alert to the public in the next week, sources said.

"When you start looking at the whole broad spectrum and look at it all together, you come up with a synergistic kind of thing that raises a whole lot of concern," said one Defense Department official. "There is a definite upswing in chatter out there about attacking our targets."

FBI and CIA officials have taken a more cautious position, however, arguing that the threat information -- while clearly troubling -- is vague and contains no specific, credible evidence of an impending attack, sources said. One Justice Department official said the volume of reports is larger than normal, but does not approach the levels seen in the days leading up to the July Fourth holiday or to the first anniversary of the Sept. 11, 2001, terror attacks.

Many of these officials believe that issuing a general terrorism alert would alarm the public without providing any usable information, and would be viewed with undue skepticism because of U.S. preparations for war with Iraq.

"There is some feeling that parts of the administration would like to push this to get people geared up" for Iraq, one law enforcement official said. "It's not that we've learned specific information that needs to be communicated to the public. If we did a public warning, it would have to be very general."

One defense official said that the Defense Intelligence Agency has collected information overseas indicating a possible attack within the United States. But FBI officials have not been able to confirm those reports and are skeptical of their veracity, the official said.

A decision on whether to issue a general alert has been delayed in part so the FBI and other authorities can investigate several specific threat reports that might be corroborated or discounted, either through interrogations of U.S. military detainees overseas or through traditional law enforcement work, one official said.

The nation's color-coded threat index remained at yellow yesterday, signifying an elevated risk of terrorist attack. That level has been upgraded only once to orange, which signifies a "high" risk of attack, and officials said there were no immediate plans to increase the level. "We remain concerned about continued al Qaeda activity overseas as well as al Qaeda sympathizers here in the United States," said Gordon Johndroe, spokesman for the Department of Homeland Security, which is responsible for the threat index. "Should additional information and analysis develop requiring the threat level to be raised, we will keep the American public informed as always."

This week's National Intelligence Bulletin, issued by the FBI to about 17,000 law enforcement agencies nationwide, is expected to include cautions about particular buildings and events that could be inviting targets for Islamic extremists, sources said. One example that may be cited is the 90th anniversary celebration of the Anti-Defamation League, a national Jewish organization, which begins today in Palm Beach, Fla., officials said.

The bulletin was originally scheduled to be released yesterday afternoon but, after delays for additional review, may not be released until today, officials said.

Vincent Cannistraro, a former CIA counterterrorism official who maintains contacts with the U.S. intelligence community, said that despite the debate over a public warning, intelligence officials throughout the government agree that the volume of threats is alarming.

"They can't focus that concern on any one specific area, but they are reading the same material and saying it's quite possible something big is going to happen," Cannistraro said. "There is a lot of worry. They have intelligence indicating that something is planned for this year, but they don't know where or how or exactly when."

Staff writers John Mintz and Dana Priest contributed to this report.