IRAQ: US and Iraqi forces are pressing on with a highly publicised offensive against suspected guerrillas north of Baghdad in their latest drive to weaken a raging insurgency.
Operation Swarmer was mounted as Iraqi leaders failed again in talks to form a national unity government widely seen as vital to avert any slide into civil war from high sectarian tensions between the majority Shia Muslims and Sunni Arabs.
Signs of movement to end the paralysis have emerged with US and Iranian officials saying they could set aside years of hostility to discuss stabilising Iraq, where Tehran has gained influence with ties to fellow Shias in power.
US military officials said on Thursday that the operation, in which 1,500 US and Iraqi troops and 50 helicopters had been deployed, was the biggest air assault since a similar airlift just after the war to oust Saddam Hussein three years ago.
Military spokesman Lieut Col Barry Johnson said the operation near the town of Samarra involved searching a 16km x 16km (10-mile x 10-mile) area for guerrillas, who gather support from the Sunni community, dominant under Saddam. No casualties were reported by US or Iraqi forces.
Lieut Col Johnson said 50 people had been detained and 30 remained in custody as a result of the operation near Samarra, where an alleged al-Qaeda bomb destroyed a Shia shrine last month and triggered weeks of sectarian bloodshed.
The operation, just before the third anniversary of the US-led invasion, appears to be the latest US effort to show that Iraqi troops are improving their performance against insurgents.
A US troop withdrawal hinges on whether Iraq's army - disbanded in 2003 by US authorities and now being rapidly rebuilt - can improve its capability in the face of a raging insurgency and surge in sectarian killings.
British defence secretary John Reid said the operation demonstrated the growing strength of the Iraqi army.
"This operation is Iraqi-led, something that on this size and scale would not have been possible 12 months ago," Mr Reid, in Baghdad to meet Iraqi ministers, told reporters.
The US ambassador to Iraq, Zalmay Khalilzad, has been mediating in hopes that Iraqi leaders will finally bury sharp differences and form a national unity government three months after parliamentary elections.
Iraqi leaders met in another attempt to strike a deal, but there was no outward sign of progress as they posed for the cameras at a news conference.
Political sources said there may be a breakthrough in the coming days, with the powerful but factionally divided Shia Alliance appearing more willing to consider an alternative to prime minister Ibrahim al-Jaafari. Kurdish and Sunni leaders want to see him dropped.
New violence reminded all parties of the enormous challenges that lay ahead almost three years since Saddam was toppled and Iraqis were promised a bright future. A suicide bomber got on to a bus and detonated his explosives belt, killing the driver and wounding four people nearby, police said.
Three bodies with gunshot wounds to the head and signs of torture were found in Baghdad, apparently part of the latest wave of sectarian violence that has left more than 100 corpses dumped in the capital alone since Monday.
South of Baghdad in Mahmudiya, in an area known as the triangle of death for its insurgent attacks, two Shia pilgrims walking to the holy city of Kerbala were killed by a roadside bomb, police said.
Another roadside bomb killed a policeman in nearby Latifiya.