Rioters rampage in Geneva as activists gear up for anti-G8 action.

(From Agence France Presse)

Anti-globalisation rioters rampaged through Geneva overnight, smashing shop windows and hurling firebombs at government buildings as demonstrators geared up for major protests to mark the opening of a G8 summit.

The trouble flared just hours before leaders of the world's most powerful nations were due to arrive across the border in the French Alpine resort of Evian for their three-day annual meeting.

Tens of thousands of anti-globalisation activists are expected to join cross-border protests to air a multitude of grievances against the world's invitation-only rich club.

To counter the threat, some 25,000 police and military personnel have been deployed in Evian and just across the Swiss border in Geneva to try to ensure the high-profile summit passes off peacefully.

Security is so strict in Evian itself that the protestors have been forced to focus their campaign around Geneva and the French town of Annemasse, setting up vast tent camps.

Protestors, some wearing masks, blocked a road and bridge on both sides of the border but riot police used tear gas to stop a group trying to reach Thonon, about 10 kilometers (six miles) from the heavily-fortified summit site.