"We are not exaggerating when we say that the number of deaths in the ranks of the crusader army is 10 times higher than the 2,000 announced in the pernicious media," the group said in a website statement.
"Their forces have encountered difficulties disposing of the corpses which they are burying in mass graves in the desert, throwing in the rivers, or incinerating."
No evidence is offered for the claims.
Three US soldiers were killed on Saturday in two incidents in Iraq, the US military announced, as two more US servicemen were reported dead in neighbouring Kuwait.
The latest deaths bring to 2,013 the number of US military personnel killed in the Iraq operation since the March 2003 invasion, according to an AFP tally.
That figure closely tallies with the official Pentagon count and the toll figures published by the independent Iraq Coalition Casualty Count website (icasualties.org)
The Pentagon also lists more than 15,000 troops wounded since the start of the war.
Use the old method: Take "their" claimed number and "our" claimed number AND the "real" number is most probably between the two.