Six years after the U.S.-led invasion to oust Saddam Hussein, Iraq declared a public holiday Tuesday to mark the planned withdrawal of U.S. troops from cities and towns, staging a military parade aimed at illustrating its security progress.

A suicide bomber detonated a truck filled with explosives Friday outside an Iraqi base in Mosul, killing five U.S. soldiers and two Iraqi policemen in the deadliest attack for U.S. forces in more than a year, according to the U.S.