Thirty-two people were arrested on Wednesday when they tried to block entrances to the Internal Revenue Service in protests marking the fifth anniversary of the U.S. invasion of Iraq, police said.

Protesters also picketed news organizations and defense contractors and blocked traffic in several antiwar events across the country as the Iraq war entered its sixth year.

On the National Mall, about 100 protesters carried signs that read "The Endlessness Justifies the Meaninglessness" and waved upside-down U.S. flags, a traditional sign of distress.

"Bush and Cheney, leaders failed, Bush and Cheney belong in jail," they chanted, referring to U.S. President George W. Bush and Vice President Dick Cheney.

Protesters had hoped to shut down the IRS, the U.S. tax collection agency, to highlight the cost of the war. Police cleared the building's entrances within an hour.

Immigration and Customs Enforcement spokeswoman Ernestine Fubbs said 32 people were arrested when they crossed barriers set up by police. Other police officials said the event was nonviolent.

One hour after the IRS standoff, several dozen protesters waved signs that said "Stop Paying to Kill" and "How Much Longer?" as a ragtag brass band played. IRS employees were easily able to enter the building.

"We wanted to put our bodies between the money and what that money goes to fund -- the war, the occupation, the bombs," said Frida Berrigan, an organizer with the War Resisters League.

"It would have been nice to shut down the building for the whole day but I think this was a good symbolic action," she said.

BLOCKING TRAFFIC

Later, scores of noisy protesters blocked a busy intersection in the city's business district. They picketed in front of the offices of The Washington Post and threw red paint on the building that houses the Examiner newspaper and Bechtel National Inc., which has handled major reconstruction projects in Iraq.

In San Francisco, several hundred people protested along Market Street in the central business district on Wednesday. A police spokesman said officers had made some arrests but did not have an exact count or details on the charges.

Four women were detained for hanging a 20-foot-long (6-metre-long) banner off the city's Golden Gate Bridge and then released, said bridge spokeswoman Mary Currie.

In New York, about 30 members of the "Granny Peace Brigade" gathered in Times Square, knitting in hand, to demand that troops be brought home now.

"We're out here to show people that this war is madness. We never should have gotten into this war in the first place," said Shirley Weiner, 80.

Berrigan said she was disappointed that antiwar protests have shrunk in size over the past five years, in contrast to the massive protests of the Vietnam War era, when her father, Philip Berrigan, was prominent in the antiwar movement.

"The war is an abstraction to a majority of Americans," she said.