Iraq war protesters are planning to converge on Washington next month and several organizations, including the POW-MIA group Rolling Thunder, are banding together to protect sacred ground for Vietnam War veterans.

The rally March 17 against the war, organizers say, is to get under way in a grassy park near the Vietnam Veterans Memorial, known as the wall.

Two veterans' groups said Wednesday they fear protesters may deface the memorial, a claim dismissed by the demonstrating groups.

"We're going there to protect our memorial and show support for our troops," said Artie Muller, founder and executive director of Rolling Thunder.

Muller said he and other veterans grew concerned because during a January anti-war rally, some protesters spray-painted graffiti on the steps of the Capitol.

Richard Becker, a spokesman for the upcoming rally, said the organizations involved have no intention of desecrating the black granite memorial wall. "I think it's the spreading of myths and that's a polite way of putting it," Becker said.

The anti-war ANSWER (Act Now to Stop War and End Racism) Coalition is organizing the protest to coincide with the fourth anniversary of the U.S.-led invasion, which was launched on March 20, 2003, in Iraq.

Becker declined to estimate the number of protesters expected. He said the crowd will include some Iraq war veterans and their families.

From the Vietnam War Memorial, the protesters plan to march to the Pentagon to demand an immediate withdrawal of U.S troops from Iraq.

Larry Bailey, a retired Navy captain, said he and other Vietnam veterans aim to guard entrance points to the wall to keep protesters away. "They stand for things that are a total anathema to those of us who were the next generation after the 'great generation,"' he said.

In late January, tens of thousands of protesters marched in a Washington anti-war demonstration. The rally drew celebrities including Jane Fonda and Sean Penn as well as active-duty service members.

A small group of demonstrators managed to spray-paint the steps on the west side of the Capitol. Capitol Police said the writing was cleaned off quickly.