LONDON -- Demonstrations against next week's G8 summit in Northern Ireland have begun in London with police reporting six arrests on Tuesday.

An Associated Press photographer reported minor scuffles Tuesday between police and demonstrators making their way to a "Carnival Against Capitalism" planned by the group StopG8.

Ahead of the protests, riot police also swooped in on a building occupied by the anti-G8 protesters. Video footage showed officers in climbing gear on the building's roof, tackling a protester.

Scotland Yard said six people have been arrested for a variety of alleged offences, including assault on police and criminal damage.

Leaders from the Group of Eight will meet in Lough Erne, Northern Ireland, on June 17-18.