BAGHDAD -- Pleading for her life between terrified sobs, kidnapped aid official Margaret Hassan appeared on a videotape Friday urging British Prime Minister Tony Blair to abandon Iraq and not to assist the United States in preparing for an assault on Fallujah.

"Please help me, please help me. This might be my last hour," Hassan, the director of CARE International's operations in Iraq, said on the video delivered to the satellite television network al-Jazeera. "Please, the British people, ask Mr. Blair to take the troops out of Iraq and not to bring them here to Baghdad."

Hassan, a native of Ireland who married an Iraqi and moved to Baghdad 30 years ago, was seized Tuesday morning outside the west Baghdad office of CARE. She is the best-known and highest-ranking aid official among the roughly 150 foreigners and Iraqis kidnapped here in recent months. No one has yet asserted responsibility for her abduction.

In the video, Hassan said her abductors had linked her fate to the actions of Britain. The Blair government previously announced that it had agreed to a Pentagon request to shift troops from southern Iraq to an area just south of Baghdad to relieve U.S. troops needed for an assault on Fallujah.

"That is the reason behind kidnapping people like me and Mr. Bigley," Hassan said, referring to Kenneth Bigley, the British engineer whose beheading was broadcast on the Internet this month after he had made similar videotaped appeals to Blair.

"Please, please, I beg of you," Hassan said in a choked voice, before burying her face in a handkerchief.

In a statement, Britain's foreign secretary, Jack Straw, called the Hassan video "distressing" but offered no concessions. "I have the greatest sympathy for what her family is suffering," Straw said. "Margaret Hassan has spent more than 30 years working for the Iraqi people. We hope all Iraqis will join us in calling for her immediate release."

U.S. Marines meanwhile continued to probe the outskirts of Fallujah, 35 miles west of Baghdad, exchanging fire for a second day with insurgents who have held the city since April.

Sunni Muslim clerics warned that an assault on the city would risk widening the insurgency ahead of elections planned for January. U.S. and Iraqi officials say the election is the reason they have threatened to strike Fallujah, arguing that it is crucial that voters in Iraq's Sunni Triangle be included in balloting.

Talks aimed at a peaceful handover of Fallujah to Iraqi forces were disrupted by the interim Iraqi government's demand that city leaders give up foreign fighters led by Abu Musab Zarqawi, the Jordanian blamed for kidnappings, beheadings, car bombings and other attacks. Tensions rose further Friday as word spread of the arrest by U.S. forces of Abdul Sattar Abdul Jabbar, a prominent official in the Association of Muslim Scholars, which represents Iraq's Sunni clerics.

"We ask the government, what did Sheik Abdul Sattar do? Does he have Zarqawi?" a fellow cleric, Hareth Ubeidi, said in a sermon at the Baghdad mosque where the association is headquartered. The group vociferously opposes the presence of U.S. troops in Iraq.

Muthana Hareth Dhari, the son of the association's leader, called the arrest "a dangerous escalation from the side of the occupier."

The warnings by Sunni clerics stood in contrast to the tenor of Friday prayers in a key Shiite Muslim mosque. Preaching in Sadr City, the Baghdad slum where Shiite militiamen have spent much of the last two months fighting U.S. forces, a cleric representing Moqtada Sadr counseled a shift from violence to politics. Historically shut out of power, Shiites account for the majority in Iraq and stand to gain by elections.

"We want to set an example for other unarmed peoples who want to carry out the struggle against aggression and occupation by peaceful means," said Abdul Zahra Suwaidaee, a senior Sadr aide.

Iraqi officials have urged Sadr to disband his militia, which for the last week was paid to turn in its heavy guns in a program that Iraqi officials called a success but that left U.S. commanders unimpressed. Whatever the outcome -- and commanders say the militia has yet to dig up and disarm scores of booby traps buried in the slum's fetid streets -- Sadr officials continue to preach peace.

"We reaffirm our rejection of the foreign presence and concentrate on achieving unity among the people, for we are soldiers and messengers of peace and guidance," Suwaidaee told worshipers. "The major and basic challenge facing us is cultural, because we do not want freedom and prosperity devoid of integrity, and we must keep in mind that struggle can be waged not only by guns."

In the continuing legal proceedings stemming from abuse of Iraqi detainees at Abu Ghraib prison last fall, a military judge on Friday set a Jan. 7 court-martial date for Spec. Charles A. Graner Jr., the Army Reservist alleged to be the ringleader in the abuse.

During the military equivalent of a pretrial hearing, the judge, Col. James Pohl, denied a request by Graner's attorney that witnesses be given immunity if they testified during his court-martial. The hearings came a day after Staff Sgt. Ivan L. "Chip" Frederick II was sentenced to eight years in prison for his role in the abuse scandal. Frederick had pleaded guilty in exchange for a lighter sentence. Graner could be sentenced to as much as 28 years.

"We are going to win," Graner's civilian attorney, Guy Womack, said after the hearing. "He was acting under fully lawful orders at the time."

Paul Bergrin, the civilian attorney for Sgt. Javal S. Davis, who faces 81/2 years if convicted, said his client would also plead not guilty. "Our position is that there was legally improper and unlawful command influence at the highest level," Bergrin said.

Correspondent Jackie Spinner and special correspondents Bassam Sebti and Khalid Saffar contributed to this report.

In a tape shown on Arab television, Margaret Hassan, director of CARE operations in Iraq, said her fate depended on Britain's actions.Residents of a town near Fallujah demanded release of two Iraqi women arrested by U.S. forces in a raid on the city.