A US military transport helicopter has crashed near Baghdad, the fifth such aircraft lost in Iraq in three weeks.
Witnesses reported seeing an aircraft in trouble during gunfire from the ground. US military spokesman Major-General William Caldwell would not say whether there had been any casualties.
Mr Caldwell confirmed that a CH-46 helicopter went down and said a quick reaction force was on site.
The helicopter was a twin-rotor Sea Knight, which can carry up to 25 passengers and four crew.
The US military said it was adjusting its tactics after four helicopters were shot down in separate incidents over a two-week period, which saw 21 servicemen and private security contractors die.
Bremer defends US cash for Iraq
The former head of the US civil administration in Iraq, Paul Bremer, has defended the sending of billions of dollars in cash to Baghdad in 2003 and 2004.
The money consisted of funds from Iraqi oil exports and frozen assets of the Saddam Hussein regime.
Mr Bremer told a US Congressional Committee that it had been impossible to apply modern accounting standards during the distribution of the money.
