LONDON, Ont. -- Police moved in early Wednesday and removed Occupy protesters from a city park.

Dozens of officers surrounded the park at about 12:30 a..m., as Day 18 of the protest began, ordering the occupiers to vacate or risk trespassing charges.

The city had ordered the protesters to vacate the park by 6 p.m. Tuesday, and were told they'd be charged after 10 p.m.

But as police stood by as both deadlines passed, up to 150 occupiers remained.

When it looked like police were standing down, protester Neil Hamell said he wasn't surprised city officials didn't follow through on the threat.

"There's too many people here," Hamell said. "It shows the strength in the movement."

But all that changed after many supporters and onlookers left and protesters settled in for the night.

That's when police swooped in, becoming the first authorities in Canada to move against one of the many U.S.-inspired Occupy Movement camps that have sprung up across the country.

In Vancouver, the city is going to court to seek an injunction to legally oust the campers.

Mayor Gregor Robertson initially took a soft stand against the protesters but changed his tune after a camper's near-fatal heroin overdose, which was followed by the death of a young woman, also suspected of overdosing. On Tuesday, two officers were sent to hospital after being bitten and beaten during a scuffle with protesters.

Police Chief Jim Chu said Tuesday protesters formed a human chain to prevent fire officials from putting out a fire in a barrel at the site just before midnight.

"Our officers received the full wrath of the protesters, who punched, kicked and bit them," Chu said, adding one officer had a gun clip stolen.

"This can no longer stand. We are issuing a public warning to those who remain on the site. It is time to leave."

Meanwhile, in Toronto, Mayor Rob Ford said the Occupy encampment at St. James Park needs to go and soon.

"They've had a peaceful protest, but I think it's time we asked them to leave," Ford said.

He said he's trying to schedule a meeting with police Chief Bill Blair about the issue, but hasn't been able to yet.

The mayor said there's no doubt in his mind bylaws are being broken at the camp, occupied by about 500 people.

As well, he said, the park's sprinkler system must be readied for winter or it will be damaged.

Ford set no deadline for clearing the park though, nor did he discuss how the city would manage to clear it if the protesters don't want to leave.

At Victoria's Occupy encampment, a man was taken to hospital Tuesday night after police convinced him to get down out of a tree. Police said they were concerned for the 47-year-old's mental health. Earlier in the day, the man allegedly dumped a bottle of urine on a city employee. That alleged assault remains under investigation.

-- with files from Stephanie Ip, Greg Colgan and Jonathan Jenkins