Also yesterday, in a full-page newspaper ad, Iraq 's top Shia Muslim cleric reiterated his demand for the country's next legislature to be elected as he hardens his opposition to US plans for regional caucuses.

The 1st Armored Divison soldier killed was the first reported combat death among US troops in Iraq since Friday, when nine soldiers were killed when a Black Hawk medevac helicopter was shot down near Fallujah.

US officials say incessant attacks by anti-American insurgents have declined in frequency since the capture of Saddam Hussein, with an average of 17 attacks a day against US troops in the past week compared to 30 a day before Saddam was seized Dec. 13.

Most of the total US casualties in Iraq have occurred since President Bush declared an end to major combat May 1 -- and many of have been caused by insurgent ambushes and roadside bombs like the one Monday, which brought the American death toll to 496. Details including the soldier's identity were not immediately available.

Another roadside bomb explo-ded Monday near an Army convoy in Ramadi but the military said no US casualties were reported. Local residents said two Iraqis were killed when the Americans opened fire after the attack.

Earlier Monday, the US military said that US soldiers uncovered a "large weapons cache" on Friday with the help of an Iraqi in Ramadi, a town west of Baghdad.

The Iraqi led the troops to a house, where they found dozens of rocket-propelled grenades and a handful of launchers, nearly 220 pounds of explosives, 16 remote controlled homemade bombs and two surface-to-air missiles, the military said in a statement.