BAGHDAD, Oct 20: Iraq suffered a fresh blow on Wednesday as the foreign aid group CARE halted its operations in the violence-wracked country after the kidnapping of a top relief worker, while a car bomb blew up in Baghdad.

US-led air raids, meanwhile, destroyed two alleged safe houses of militant Abu Mussab al-Zarqawi's network in the rebel-held city of Fallujah, the military said.

They struck "two adjoining Abu Mussab al-Zarqawi terrorist safe houses in northeast Fallujah," it said in a statement. There was no immediate report of casualties.

The kidnapping of the CARE official and latest violence once more undermined efforts by the US-backed interim government to restore stability ahead of national elections promised in January.

Margaret Hassan, who was born in Ireland and has lived in Iraq for three decades, was kidnapped by gunmen on her way to work in Baghdad on Tuesday in the latest hostage crisis that has already claimed scores of foreign and Iraqi lives.

Britain, Ireland and the United States condemned the abduction and said they would work to release CARE's top Baghdad staffer, who has both British and - through her husband - Iraqi citizenship.

"This is someone who has lived in Iraq for 30 years, someone who is immensely respected, someone who is doing their level best to help the country," British Prime Minister Tony Blair said.

He was speaking just days after another hostage, Kenneth Bigley, became the first Briton to be beheaded in the war-battered country.

Britain's embassy in Baghdad said it was working with the Iraqi authorities to establish what had happened. "Consulate officials are in touch with next of kin," a spokeswoman added.

Ms Hassan's abduction was a further sign of the insurgents' willingness to strike at workers from humanitarian agencies, after two Italian aid workers were taken in early September. The two women were released after a three-week ordeal.

Adding to the tension in Baghdad, a suicide car bomb exploded on Wednesday on the road to the international airport, killing only the driver, while a roadside bomb blew up near a US vehicle but caused no casualties, the US army said.

"There was a VBIED (vehicle-borne improvised explosive device) on the airport road but there were no civilians around and no multinational forces," said spokesman Major Philip Smith.-AFP