Defiant anti-Wall Street protesters in Washington vowed to remain peacefully entrenched in two parks near the White House despite a police order to stop camping on federal land, raising the spectre of possible confrontation.

The US National Park Service, in its first challenge to the demonstrators, said last week it would start enforcing a ban at noon (5pm Irish time) against camping in McPherson Square and Freedom Plaza, where protesters have camped out since October.

It ordered bedding and cooking equipment removed but said tents could remain as a protest symbol if flaps stayed open.

While many protesters said they would comply with the order, blankets were still visible in some tents.

After a cursory inspection of the McPherson Square camp, police remained on the outskirts and no arrests had been reported by late afternoon.

Protesters said police appeared hesitant to move in while television crews thronged the area.

In Charlotte, North Carolina, city police began evicting another group of Occupy protesters from city property today.

Despite their small numbers, the Washington protesters enjoy a lot of media attention because their camps are just blocks from President Barack Obama's official residence.

One camp is next to K Street, a wide thoroughfare that is home to many lobbyists and is synonymous with corporate influence in the capital.

While Mr Obama has not explicitly backed the protests, he has made economic inequality a central theme of his re-election campaign and called for higher taxes on wealthier Americans, angering his Republican opponents.

McPherson Square protesters set up a huge tent decorated with stars and moons over a statue of Civil War General James McPherson in the centre of the square to protest the police order.

"The people united will never be defeated," they chanted.

Tension rose in the "Occupy DC" camps after police used a stun gun on one protester yesterday.

More than 400 people were arrested during violent anti-Wall Street protests in Oakland, California over the weekend.

Some Washington protesters said they would defy the park police order while others said they would sleep in churches and elsewhere.

They are permitted to hold overnight vigils in the parks overnight so long as they do not use their tents for sleeping or cooking.

A US Park Police spokesman said arrests would be made on a case-by-case basis.