WASHINGTON, April 13: Some convoys ferrying supplies for US troops in Iraq have been suspended until the military can provide better security for them, the Army and its top contractor said on Tuesday.

Dan Carlson, a spokesman for US Army Materiel Command in Rock Island, Illinois, said some convoys bringing in supplies had been delayed after a string of attacks and hostage-takings involving contractors.

"We are assessing what the impact of those delays will be," said Carlson, adding that he could not provide further details of what supplies were being held up and whether this could affect military operations.

The US military's main logistics contractor in Iraq is Texas-based Kellogg Brown and Root, a subsidiary of oil services giant Halliburton, Vice President Dick Cheney's former company. The KBR has more than 24,000 employees working in Iraq. -Reuters