BAGHDAD -- Violence killed at least 26 people yesterday, including three US soldiers, and mortar fire rumbled through the heart of Baghdad after sundown despite stringent security measures imposed after an explosion of sectarian violence.
Iraqi police said they had found no trace of abducted American journalist Jill Carroll as the deadline set by her kidnappers for killing her passed at midnight with no word on her fate.
A ban on driving in Baghdad and its suburbs helped prevent major attacks during daylight yesterday, but after nightfall explosions thundered through the city as mortar shells slammed into a Shi'ite quarter in southwestern Baghdad, killing 16 people and wounding 53, police said.
Mortar fire also hit a Shi'ite area on the capital's east side, killing three people and injuring six, police reported.
Nevertheless, officials announced they would let vehicles back on the streets at 6 a.m. today -- in part because shops were running out of food and other basics. Gasoline stations were closed, and people were unable to go to work yesterday, a work day in this Muslim country.
The vehicle ban, which followed a curfew that kept everyone in the Baghdad region inside for two days, was part of emergency measures imposed after Wednesday's bombing of a Shi'ite shrine in Samarra triggered a wave of reprisal attacks on Sunni mosques and clerics, pushing Iraq to the brink of civil war.
The crisis distracted attention from the deadline set by Carroll's kidnappers.
The freelance journalist, who was doing work for the Christian Science Monitor, was abducted Jan. 7 in Baghdad. She was last seen on a videotape broadcast Feb. 10 by a Kuwaiti television station that said the kidnappers threatened to kill her unless the United States met unspecified demands by yesterday.
An Interior Ministry official said yesterday that authorities had stepped up their search for Carroll, 28, but made no progress.
''Our forces raided some suspected places, but she was not there," Major Falah al-Mohammedawi said. ''We are watching the situation closely."
Although mosque attacks have declined sharply, sectarian violence went unabated yesterday.
A bomb exploded at a Shi'ite mosque in the southern city of Basra, injuring at least two people, police said.
More than 60 Shi'ite families fled their homes in predominantly Sunni areas west and north of Baghdad after receiving threats, said Shi'ite legislator Jalaladin al-Saghir and Iraqi army Brigadier General Jalil Khallaf.
North of the capital, gunmen stepped from a car and fired on teenagers playing soccer in a Shi'ite-Sunni mixed neighborhood of Baqouba, killing two of the youths and wounding five, police said.
In other violence, two US soldiers died when their vehicle was struck by a roadside bomb in western Baghdad, the US military said. A third US soldier was killed by small-arms fire in central Baghdad late yesterday, the military said.
A roadside bomb also exploded near a police patrol in Madain south of Baghdad, killing one officer and injuring two, police said.
To the west, gunmen killed a former general in Saddam Hussein's army as he drove his car in Ramadi, a relative said. Former Brigadier General Musaab Manfi al-Rawi was rumored to be under consideration to be military commander in the town, an insurgent hotbed, said his cousin, Ahmed al-Rawi.
Gunmen in a speeding car also seriously wounded an Iraqi journalist, Nabila Ibrahim, in Kut, southeast of Baghdad.
The sectarian crisis threatened US plans for a government drawing in the country's major ethnic and religious parties, considered essential to win the trust of the disaffected Sunni Arab minority that forms the backbone of the insurgency.
With a broad-based government in place, the Bush administration hopes to begin withdrawing some of its 138,000 soldiers this year.
A former British ambassador to Iraq predicted yesterday that increasing sectarian bloodshed would require the US-led foreign military coalition to stay for some time to help keep peace among rival ethnic and religious groups.
''One could almost call it a low-level civil war already," Sir Jeremy Greenstock, Britain's envoy in Baghdad until 2004, told British television channel ITV1.
During a meeting at Prime Minister Ibrahim al-Jaafari's residence, representatives of the main political parties agreed late Saturday to renew efforts to form an inclusive government.
But Sunni politician Nasir al-Ani said yesterday that his side was looking for some tangible steps before ending their boycott of government talks.
Sunni and Shi'ite religious leaders have also called for unity and an end to attacks on each other's mosques.
Radical Shi'ite cleric Muqtada al-Sadr, whose militia was blamed for many of the attacks on Sunnis, repeated the appeal yesterday when he addressed followers in Basra upon his return from Iran.
He accused Americans and their coalition partners of stirring up sectarian unrest and demanded their withdrawal.