BAGHDAD (AFP) - At least 20 Iraqis were killed and more than 200 wounded in fresh violence across Baghdad, as a British hostage whose two US colleagues were savagely beheaded pleaded for his life in a video on an Islamist website.
The US army launched a fresh offensive on Baghdad's radical Shiite stronghold of Sadr City overnight that killed 13 people.
And a suicide car bomb targeting recruits for the Iraqi national guard ripped through a busy shopping area in central Baghdad, killing seven people.
In northern Iraq, a US soldier was killed in an attack on a patrol in the city of Mosul, while another American soldier died in a roadside bomb attack in Tikrit, the hometown of ousted president Saddam Hussein, the US military said.
Time was running out for Kenneth Bigley, a British engineer kidnapped by militants from an Al-Qaeda-linked group headed by Abu Mussab al-Zarqawi, whose two US colleagues had their heads hacked off earlier this week.
A video posted on an Islamist website and allegedly recorded by Zarqawi's group showed what it said was Bigley pleading to British Prime Minister Tony Blair to save his life.
In the video, which could not be authenticated, the presumed hostage, whose face is blurred, urges Blair to release Iraqi women prisoners, as his captors are demanding.
"I need you (Blair) to be compassionate as you always said you were ... I don't want to die ... Please, please release the female prisoners that are held in Iraqi prisons," he said, breaking into tears.
But British Foreign Secretary Jack Straw conceded there was little hope of obtaining Bigley's release, saying London would stand firm on its refusal to negotiate with "terrorists".
"We continue to do everything we can to secure Kenneth Bigley's safe release, but it would be idle to pretend that there's a great deal of hope," Straw told BBC radio.
"We cannot get into a situation, and I believe the family understands this, where we start bargaining with terrorists and kidnappers," he said.
The United States will never negotiate with terrorists, US Secretary of State Colin Powell said, flatly ruling out any policy change in the wake of the beheading of the US hostages.
"The terrorists want to shake our will, but they will not. It shows the true barbaric nature of the enemies we face in Iraq, that they would take innocent civilian life. But they will be defeated," the White House said.
Bigley's chances of escaping the same fate as the Americans appeared slim after the US embassy and the Iraqi government denied that the release of an Iraqi woman held by the coalition was imminent.
Amid conflicting reports, the Iraqi justice ministry had said earlier that one of two women biologists in coalition hands may be freed, offering a glimmer of hope to Bigley's family.
In Italy, press reports said the Italian secret service had made indirect contact with the kidnappers of two female aid workers captured in Iraq two weeks ago and believed the hostages were still alive.
"A channel has been opened in Iraq and has provided information about the fate of the two young women," Simona Pari and Simona Torretta, according to Italy's leading daily, Corriere della Sera.
On the military front, the US push during which 13 people were killed and 149 wounded in the Shiite bastion of Sadr City in Baghdad was described by an official from firebrand cleric Moqtada Sadr's office as the "most devastating" offensive there since Saddam's fall.
US military officials claimed they had killed up to 25 fighters from Sadr's Mehdi Army and that the raid was aimed at stabilising the area and allowing reconstruction work to begin in earnest.
The next two weeks are likely to be decisive in the fight against militants and efforts to disarm militiamen and prepare the ground for elections in January 2005, Iraq's national security advisor said.
"Our vision is that in a matter of a couple of weeks we can reduce the presence of terrorists," Kassem Daoud told reporters, promising more largescale Iraqi-US operations on the ground.
The Baghdad car bomb Wednesday that ripped through a queue of men queuing up to join the Iraqi national guard was the latest in a long list of attacks against Iraqi security forces and a recent surge of attacks in the capital.
Fresh fighting also erupted in the city's Sunni stronghold of Haifa Street, which is a mixture of smart high-rises and impoverished alleyways harbouring a loose alliance of Saddam loyalists and Islamic insurgents.
But as the US presidential race was heating up, President George W. Bush prepared to enlist the support of Allawi to boost his message and fend off criticism of his Iraq policy by his Democrat presidential rival John Kerry.
In Brussels, NATO member states finally reached agreement Wednesday on launching a full-blown training mission for Iraqi security forces.
"Today ambassadors agreed to give direction to the military to further develop the mission," NATO spokesman James Appathurai told reporters. "That guidance includes ... the establishment of an Iraqi center of excellency."
The agreement came following a week of diplomatic scrambling after objections by France to details of the accord held up its adoption.