Fallujah is no longer a safe haven to terrorists, but it is still home to many of them.

U.S. officials said the military coalition has eliminates neither the insurgency command nor most of the fighters based in Fallujah. They said most of the insurgents were believed to have fled Fallujah or melted in the general population and were preparing to resume attacks as soon as the bulk of the coalition force left the city.

"The issue for us at Central Command is make sure we keep the pressure on the terrorists and not allow another safe haven to occur, and we're going to do that," Lt. Gen. Lance Smith, deputy chief of U.S. Central Command, said on Thursday.

A seven-page Marine Corps intelligence report warned that Sunni insurgents would return to Fallujah in wake of the departure of coalition troops, Middle East Newsline reported. The report, first published in the New York Times on Thursday, asserted that Sunni insurgents were preparing to renew fighting against Iraqi police and security forces in Fallujah within the next few weeks.

"The enemy will be able to effectively defeat I MEF's [1st Marine Expeditionary Force's] ability to accomplish its primary objectives of developing an effective Iraqi security force and setting the conditions for successful Iraqi elections," the report said.

A major concern cited by the report was that Sunni insurgents would wait until the Jan. 27 elections before launching a nationwide revolt. Marine intelligence was said to have envisioned insurgency attacks throughout Iraq on election day in an effort to undermine the post-Saddam Hussein regime in Baghdad and discourage the United States from continuing efforts to stablize the country.

On Thursday, Marine units blew up insurgency weapons caches seized over the last 12 days. Officials said the Marines found stockpiles of weapons and improvised explosive devices, such as blocks of explosives and artillery rounds, chained together and rigged like booby traps.

"There are still pockets of resistance, primarily in the southern industrial part where we have a number of people that apparently are prepared to suicidally continue their efforts," Smith told a Pentagon briefing. "We have them blocked and encircled the city, but it looks like they will fight to the death."

"We're not sure exactly who they are," Smith said. "We suspect that they are probably foreign fighters. Many of them are in there using explosive vests, prepared to take their own lives with members of the Iraqi security forces and coalition forces as they come closer and closer to apprehension."

Officials said insurgents have maintained resistance and that residents of Fallujah could not yet return to their homes. They said many of the homes in Fallujah remained booby-trapped and deemed unsafe.

"We will make a recommendation to the [Iraqi] prime minister once we feel it is fairly safe and fairly secure," Lt. Gen. John Sattler, commander of the 1st Marine Expeditionary Force, said. "Once we've cleared each and every house in a sector, then the Iraqi government will make the notification for residents of that particular sector that they are encouraged to return."

Officials said the United States does not plan to withdraw forces from Fallujah. But they acknowledged that thousands of U.S. soldiers were redeployed from the city to help fight the insurgency that has erupted in other parts of the Sunni Triangle.

In Mosul, Sunni insurgents attacked the office of the governor on Thursday, killing a bodyguard and injuring another four. Insurgency attacks were also reported in Baghdad, Baiji, Kirkuk and Ramadi.

At the same time, some U.S. commanders in Fallujah have assessed that the military might have captured the command center of the Tawhid and Jihad group, headed by Abu Mussib Al Zarqawi, regarded as the most lethal insurgent in Iraq. The purported command center contained computers as well as written instructions from Al Zarqawi to two of his aides.

"I cannot stand here and tell you that we found the [Al Zarqawi] command and control house or building," Sattler said. "We will continue to look for that."