Media playback is unsupported on your device Media caption Protesters have been told they can stay in the park, but must stay out of the roads

Police in Los Angeles have arrested four people after Occupy Wall Street protesters camping outside City Hall defied an eviction deadline.

At least 1,000 people flooded into the area around City Hall Park before a midnight (08:00 GMT) deadline.

By 05:00 (13:00 GMT) police said those blocking streets would be arrested, but those staying in the park would not.

Officers carrying batons and non-lethal weapons took to the streets but faced sit-ins by angry protesters.

At a news conference on Monday, police chief Charlie Beck said that midnight was not a deadline for police action, but rather the official time the camp had become illegal.

"We will enforce the law on our own time schedule," Mr Beck said, adding that officers would take action only "when it makes sense".

The arrests were made after a few protesters refused to leave an intersection.

The Occupy camp inside the park had grown to some 485 tents, but about half were taken down before the Sunday deadline.

The city's mayor has said he hopes to avoid the confrontations between police and protesters that have marred evictions in other cities.

Antonio Villaraigosa, a former union representative, said he hoped for a "spirit of co-operation" with those camped out.

But a statement from the protesters issued on Friday dismissed his eviction demand and said the camp would remain.

'Throw a party'

As the deadline passed, some 1,000 protesters and their supporters gathered at the City Hall lawn for their traditional nightly meeting.

Image copyright Getty Images Image caption While LA police were out in force early Monday morning, few arrests were made

Hundreds of Los Angeles police wearing helmets and batons lined the streets, but there were no confrontations.

A few protesters climbed into trees while others stood or sat on the ground, the Los Angeles Times reported.

"The best way to keep a non-violent movement non-violent is to throw a party, and keep it festive," protester Brian Masterson was quoted as saying by the Associated Press news agency.

Before the early morning stand-off, police chief Beck said: "I have no illusions that everybody is going to leave. We anticipate that we will have to make arrests."

But he said officers would "not be the first ones to apply force".

Anticipating eviction, some of those camped outside had attended sessions on resistance tactics, including how to stay safe should police fire rubber bullets or use pepper spray.

I feel like if there's one moment to show solidarity with the movement, it's tonight Alex Herboche, Occupy supporter

But many said they would refuse to leave and were willing to be detained.

"Their plan is to resist the closure of this encampment and, if that means getting arrested, so be it," said Will Picard, one of the protesters.

Alex Herboche, a student, told the LA Times she came early on Monday morning to lend her support by picking up rubbish.

"I feel like if there's one moment to show solidarity with the movement, it's tonight," she said.

'Proud' mayor

Despite issuing the deadline, Mr Villaraigosa had spoken about the Occupy movement in terms not often heard from elected officials in the US.

"It is time for Occupy LA to move from holding a particular patch of park land to spreading the message of economic justice and signing more people up for the push to restore the balance to American society," he said.

The camp was unsustainable because public health and safety could not be maintained, he added, saying City Hall Park had to be cleared, cleaned and restored for public access.

The Occupy LA camp began on 1 October, shortly after the initial Occupy protest in New York City.

Protests in the city have been largely peaceful, with fewer tensions between police and those camping out than in some cities.

In Oakland, California, there were several flashpoints between police and protesters, and police also used pepper spray in breaking up an Occupy camp in Seattle, Washington.