Media playback is unsupported on your device Media caption The protesters say they are going to stay until the police clear the site

Occupy protesters have defied a noon police deadline to remove their camps or face arrest in Washington DC.

They have erected a "tent of dreams" around a statue in McPherson Square as part of their protest against eviction.

The camps at McPherson Square and Freedom Plaza have been Occupy's most visible sites since the one in New York was cleared out in November.

The deadline follows mass arrests and clashes with police at anti-Wall Street protests in Oakland, California.

No arrests had been made by late Monday afternoon.

The enormous blue "tent of dreams", decorated with crescent moons and shooting stars, bears a sign saying: "Let us sleep so we can dream", marking the intention of the protesters not to evacuate their camp.

The crowds filling the square chanted: "This is what democracy looks like!" Inside were about 18 smaller tents, pet igloos and sleeping bags.

Occupy protesters said they were expecting supporters from other cities - Philadelphia, New York, and Boston - to join them on Monday.

'Paradigm shift'

In Washington, notices handed out by police warned: "If camping violations are observed, individual violators may be subject to arrest and their property subject to seizure as evidence.

"Any temporary structure used for camping also will be subject to seizure as an abatement of a public nuisance."

The activists, who have camped continuously at the Washington DC sites for four months, will be permitted to continue demonstrating as long as they keep "one side of all temporary structures open at all times" as a safety precaution.

Image caption McPherson Square is now full of chanting, cheerful crowds

But some demonstrators say that the Monday deadline merely represented a change in tactics.

"There is no expectation that the site is coming down," Annie Storr, an activist at McPherson Square, told the Associated Press news agency. "It is a paradigm shift."

In a statement, the protesters pledged to "defend the public space we have used as our centre for activism".

On Sunday, one protester was stunned by police with a taser for tearing down notices of the deadline.

A day earlier, about 200 demonstrators staged a topless party outside a black-tie event in the US capital. Among the attendees were US President Barack Obama and his wife, Michelle.

Also on Saturday, about 400 protesters were arrested during the night in Oakland, California, as clashes broke out with police in one of the largest mass detentions since the movement began.

Police fired tear gas and smoke bombs to disperse activists as they attempted to enter the City Hall and an empty convention centre.

In response, demonstrators flung bottles, rocks and other objects at the police.

Afterwards, Occupy Oakland said on Twitter: "We didn't get in the building, but fought like our future depended on it."