Several officers grab a protester who was poking a police officer with a sign. (CBC)

While protests against the G20 summit in Toronto turned violent on Saturday, a mostly peaceful gathering in Vancouver became ugly when a group of demonstrators began kicking police officers and poking them with signs.

Vancouver police Const. Lindsey Houghton said the aggressive protesters were dressed in black and masked their faces to hide their identity.

"A core group of the black-clad protesters began to try to bait officers, who were facilitating the protest, by trying to damage police equipment, kicking the officers and taunting them," Houghton said.

He said the so-called Black Bloc tactic included protesters in the city's Commercial Drive area swearing and yelling at officers in an effort to provoke them.

"While there were no arrests today, the right to protest doesn't include the right to commit criminal acts that place the public's safety at risk," he said.

In February, Black Bloc protesters smashed display windows of the downtown Bay store in Vancouver on the opening day of the Olympics.