(AP)
Updated: 2007-08-22 17:00

A helicopter went down in northern Iraq on Wednesday, killing all 14 US soldiers aboard, the US military said, the deadliest crash since January 2005.

In a file photo a UH-60 Blackhawk helicopter lands to extract members of a US Army Combat Team, during a mission near Tall Afar, Iraq, June 5, 2006. [AP]

The military said initial indications showed the aircraft experienced a mechanical problem and was not brought down by hostile fire, but the cause of the crash was still under investigation.

The UH-60 Black Hawk was part of a pair of helicopters on a nighttime operation when the crash occurred. The four crew members and 10 passengers who perished were assigned to Task Force Lightning, the military said. It did not release identities pending notification of relatives.

The US military relies heavily on helicopters to avoid the threat of ambushes and roadside bombs -- the deadliest weapon in the militants' arsenal -- and dozens have crashed in accidents or been shot down.

The deadliest crash occurred on Jan. 26, 2005, when a CH-53 Sea Stallion transport helicopter went down in a sandstorm in western Iraq, killing 31 US troops.

Wednesday's deaths raised to at least 3,721 members of the US military who have died since the Iraq war started in March 2003, according to an Associated Press count.

Meanwhile, a suicide truck bomber targeted a police agency in northern Iraq, killing at least 19 people and wounding 26, police and hospital officials said.

The attack occurred just before noon in Beiji, 155 miles north of Baghdad, and many of the casualties were civilians, according to the officials.

Iraqi police and soldiers have frequently been targeted by militants seeking to disrupt US-led efforts to enable the forces to take over their own security so foreign troops can go home. A bomb and small-arms attack against a security post shared by police and US paratroopers also killed 13 Iraqi officers in Beiji in late June.

Jassim Saleh, 41, who lives some 500 yards away from the blast site, said he saw an explosives-laden truck carrying stones strike the police station.

"It was a horrible scene. I can't describe it," he said. "The bodies were scattered everywhere. I was injured in my hand and a leg, but I took three wounded people to the hospital in my car."

With violence unrelenting, political pressure mounted for Prime Minister Nouri al-Maliki to show progress in bringing Iraq's battling factions together.

US President Bush acknowledged his frustration with Iraqi leaders' inability to bridge political divisions on Tuesday, but said only the Iraqi people can decide whether to sideline the troubled prime minister.

"Clearly, the Iraqi government's got to do more," Bush said at the close of a two-day North American summit with the leaders of Mexico and Canada.

The Sept. 15 deadline for Bush's next progress report to the US Congress is fast approaching, leaving the president little time to show that his US troop buildup is succeeding in providing the enhanced security the Iraqi leaders need to forge a unified way forward.

Al-Maliki, who has faced accusations of having a Shiite bias that has alienated minority Sunnis, lashed out at the US criticism on Wednesday, saying no one has a right to put timetables on his elected government.

He blamed the US presidential campaign for the recent tough words from the Bush administration and from other American politicians.

"No one has the right to place timetables on the Iraq government. It was elected by its people," he said at a news conference in Damascus at the end of a three-day visit to Syria. "Those who make such statements are bothered by our visit to Syria. We will pay no attention. We care for our people and our constitution and can find friends elsewhere."

Without naming any American official, al-Maliki said some of the criticism of him and his government was "discourteous."

US Ambassador Ryan Crocker, co-author of the highly anticipated report to Congress, also said Tuesday that Washington's blueprint for reconciliation was insufficient to win back control of Iraq. Congressional benchmarks such as laws to share oil revenue and reform security services don't tell the whole story, he said Tuesday.

Crocker, who will present the report with military commander Gen. David Petraeus, called Iraq's problems difficult but fixable, arguing for more time for his diplomacy and operations by the bolstered American military force.

"Failure to meet any of them (congressionally mandated benchmarks) does not mean the definitive failure of the state or the society," Crocker said. "Conversely, to make them all would not by any means mean that they've turned the corner and it's a sun-dappled upland from here on in with peace and harmony and background music. It's just a lot more complex than that."

He echoed Bush's frustration with the lack of action by al-Maliki government's on key legislative measures.

"Progress on national level issues has been extremely disappointing and frustrating to all concerned -- to us, to Iraqis, to the Iraqi leadership itself," Crocker said. But he added that the Shiite prime minister was working "in the shadow of a huge national trauma."

While saying US support was not a "blank check," Crocker said Washington would continue backing al-Maliki's government "as it makes serious efforts to achieve national reconciliation and deliver effective governance to the people of Iraq." He stressed that it's not just al-Maliki, but "the whole government that has to perform here."