Two US servicemen were missing yesterday after their Black Hawk helicopter crashed in western Iraq, while security forces launched a fresh bid to regain control of Baghdad's violent streets.
The US military said the transport chopper went down on Tuesday in the restive province of Al-Anbar and that two of the six crew had not been found.
"The aircraft has been located. Search and rescue efforts are ongoing for two missing crew members. The remaining four are in stable condition," US Marine Corps spokesman Major Riccoh Player said.
"We are using all the resources available to find our missing comrades," he said, adding: "The incident does not appear to be a result of enemy action."
The chopper crash was the third such since May. The previous two were allegedly shot down by groups linked to terror network al-Qaeda.
The 130,000-strong US force in Iraq relies extensively on helicopters to transport troops and supplies, survey territory and carry out air strikes on insurgent forces.
Many of the roads around Iraq are not regarded as safe for ground convoys because of the risk of roadside bombs and ambushes -- the biggest cause of casualties for the military since the March 2003 invasion ended.
Iraqi and US security forces, meanwhile, formally launched the second phase of a security plan aimed at regaining control of Baghdad that has seen thousands killed in insurgent and sectarian Shiite-Sunni violence.
Phase one of Operation Together Forward began in June, but has failed to curb the violence that has seen daily bombings, shootings and sectarian killings leaving scores dead in the streets of Baghdad.
Insurgents have defied the security crackdown, carrying out deadly attacks on mosques and markets, while rival Shiite and Sunni death squads have rampaged through the capital's neighborhoods kidnapping, torturing and killing people.
The first phase of the operation brought more than 50,000 Iraqi and US troops on to the streets.
When this failed to halt the bloodshed, officials brought an extra 6,000 Iraqi police and troops into the capital, along with 5,500 US soldiers pulled in from different missions elsewhere in Iraq.
"We must dramatically reduce the level of violence in Baghdad that is fuelling sectarianism," said Major General James Thurman, commander of US-led forces in the Baghdad region.
"Iraqi and US forces will help the citizens of Baghdad by reducing the violence that has plagued this city since the Samarra bombing," he said, referring to an insurgent attack on a revered Shiite mosque in February that triggered tit-for-tat Shiite-Sunni reprisals.
Under the first phase of Together Forward, troops killed or captured 411 "murderers associated with death squads," the US statement said.