Berlin - As a boycott by German dairy farmers entered a second week, pickets remained around many milk plants and German supermarkets said Tuesday that supplies of some fresh-milk products were becoming tighter.

The protests against the falling price of milk in Europe have taken a harder edge, with police dragging away picketers from milk plants late Monday north of Hamburg.

Conservative farm leaders have denounced radical farmers for going beyond the law by mounting pickets.

Tractors remained parked across access roads to several major plants Tuesday, preventing supplies arriving from farmers who have ignored the strike and preventing packed milk, butter and yoghurt moving out to shops.

Germany's biggest groceries retailer, Edeka, said, "The full product range is no longer available in every supermarket." A discount grocery company, Tengelmann, also said there were some gaps in supply.

But the national retail federation denied there was any wide-scale shortage of milk in shops.

Among major dairy factories closed by blockades were the Hochwald and MUH milk plants in Rhineland-Palatinate state.

Eberhard Hetzner, chief of the milk industry federation representing the factories told the WAZ newspaper that his members would sue the radical farmers to force them to halt the pickets.

The DBV national farmers' union also denounced the pickets as illegal. The DBV has been hostile to the milk strike, which was organized by a different group, the BDM association of dairy farmers.

Burkhard Richter, a German lawyer specializing in competition issues, said boycotts were mostly illegal under German law. (dpa)