U.S. forces in Iraq, acting on tips from residents, today bombed and rocketed what the military said was a "known terrorist safe house" used by al Qaeda-allied insurgents near the Syrian border.

The air strikes on the building northeast of the border town of Husaybah in Iraq's western Anbar province came as Iraqi political leaders in Baghdad continued their attempts this afternoon to resolve an impasse over a new constitution.

Leaders representing the Shiite Muslim majority reportedly offered minority Sunni Muslim Arabs a compromise after President Bush made an unusual call to a key Shiite leader to encourage continued collaboration on the draft charter.

According to a statement issued by the 2nd Marine Division, Marine F-18D Hornet fighters carried out multiple air strikes after citizens in Husaybah provided information on what they said was a meeting by a large number of foreign-led terrorists in an abandoned building. The statement identified the targets as followers of Jordanian terrorist Abu Musab Zarqawi, whose group is known as al Qaeda in Iraq.

"Iraqi citizens reported that approximately 50 terrorists were in the building at the time" of the raid, the statement said. "The terrorists were using their position to attack the residents of the city with small-arms fire."

It said the F-18D aircraft "destroyed the building using a combination of precision-guided bombs and rockets" at about 4:40 p.m. local time.

There was no immediate information on the casualty toll from this afternoon's air strikes or the identity of any of the meeting's participants.

Marines have received reports in recent months of an escalation in fighting between Zarqawi's group and local Sunni tribes amid reports that al Qaeda in Iraq has been trying to wrest control of Husaybah. The statement said local Iraqi leaders and tribal chiefs in western Anbar province were resisting Zarqawi's "murder and intimidation campaign."

Bush's call to the Shiite leader, Abdul Aziz Hakim, was made Wednesday during his trip to Nampa, Idaho, to address National Guard soldiers and their families, and was first reported by the New York Times.

Bush urged Hakim to continue including Sunni leaders in the final discussions about the constitution being drafted by an elected assembly.

The call came Wednesday afternoon after some Shiite leaders advocated bypassing Sunnis, who are seeking changes in the draft, and sending the document directly to voters for ratification.

"This is an Iraqi process, but the United States is doing everything it can to assist them in meeting their own obligations and deadlines," White House spokesman Trent Duffy said today. He said the call was brief and did not elaborate on it.

Iraq's interim constitution requires a nationwide vote on the draft by Oct. 15. The National Assembly was obligated to finish it by Aug. 15, but negotiators instead engineered a one-week extension. When that deadline passed Monday, faction leaders submitted an incomplete document to the assembly and gave themselves until Thursday to produce a complete version.

The deadline passed inconclusively amid increasingly lethal confrontations between rival Shiite militias, who are fighting their own battles for political supremacy.

The most hotly disputed aspect of the constitutional talks has been federalism. While all sides agree to recognize the Kurds' existing self-rule in the north, most Sunnis hotly reject creation of a separate, largely Shiite state in the south bordering Iran, a Shiite theocracy.

But the Sunnis, who comprise about 20 percent of Iraq's population, largely boycotted the January elections that chose delegates to the assembly and now find their influence waning.

Apparently in response to Bush's call, Shiite negotiators today offered what they called their final compromise proposal to Sunnis to try to break the impasse, the Associated Press reported, quoting Abbas Bayati, a Shiite official.

He said the concessions were on the pivotal issues of federalism and efforts to remove former members of Saddam Hussein's Sunni-dominated Baath Party from public life, adding: "We cannot offer more than that."

There was no comment from Sunni negotiators. But in a sign of public opinion within the Sunni community, the country's Sunni vice president said the current draft was written only by Shiites and Kurds and is "far from the aspirations of all Iraqi people."

"We are trying to put forward the views of others," Vice President Ghazi Yawar told al-Jazeera television today. "We want this constitution to maintain the unity of Iraqi soil and give rights to all Iraqis."

Meanwhile, news agencies reported that about 5,000 Sunnis marched today in the city of Baqubah, 40 miles northeast of Baghdad, to protest the draft constitution. Some of them carried pictures of Hussein. They reportedly danced and chanted his name as they condemned plans by the Shiites and Kurds to push through the draft constitution and accused the Shiites of kowtowing to Iran and the United States.

"Bush, Bush, listen well; We all love Saddam Hussein!" crowds chanted, Reuters news agency reported. They carried placards with slogans such as, "We reject the American and Iranian constitution" and "No to a constitution that breaks up Iraq."