Police arrested more than a dozen people who crossed a barricade and blocked entrances at the Internal Revenue Service (IRS) building in Washington yesterday, at the start of a day of protests marking the fifth anniversary of the US invasion of Iraq.

Iraq War demonstrators gather outside the American Petroleum Institute in downtown Washington, Wednesday, March 19, 2008, as protesters marked the fifth anniversary of the war in Iraq. [Agencies]

A crowd of more than 100 gathered outside the IRS headquarters, chanting, "This is a crime scene" and, "You're arresting the wrong people."

A marching band led protesters down the street near the National Mall and around the IRS building before dozens of demonstrators gathered at the entrance.

The demonstrators said they were focusing on the IRS because it gathers the taxes used to fund the war.

Anti-war protests and vigils were planned throughout the day around the United States.