Concern is growing among wine merchants and producers in southern France following fresh attacks by the network of French wine militants known as CRAV.

Militants claiming to belong to the group have blown up the visitor centre at La Baume winery in Languedoc Roussillon, owned by Grand Chais de France, causing around EUR100,000 in damage, an employee for Grand Chais told just-drinks.

In another incident in recent weeks, balaclava-clad militants broke into a co-operative near the city Nimes and emptied the vats, causing an estimated EUR500,000 in damage.

The initials CRAV were found daubed on nearby walls after both attacks, indicating a return to violence by Languedoc's shadowy wine militant group, the Comite Regionale d'Action Viticole.

A senior employee at one winery attacked by a gang of masked, crow-bar wielding CRAV members back in 2005 told just-drinks: "You can imagine what it's like to have 50 masked guys coming in to your winery. We have big gates now and you have to ring on the buzzer to get in."

CRAV first emerged in Languedoc in the late 1950s, but the group traces its roots back to the great winemaker rebellion in the region in 1907. 

Violence from the group has erupted intermittently at different times of crisis for the region's wine industry. Years of poor sales, coupled with the current economic crisis, have put many small-time winemakers in Languedoc in debt, according to local unions.

Insiders refer to the group as a "resistance movement". Its aims, while relatively ambiguous, are to gain more support for French winemakers from the government.

Previous targets have included government offices, lorries transporting foreign wine and even speed cameras.