Milk producers in Brittany have threatened to escalate action against French dairy processor Entremont Alliance as a dispute over pricing deepens.

Farmers have blockaded an Entremont plant and immobilised the company's vehicles, demanding a 17% increase in the price of milk. Entremont has said it will not accept a hike of more than 11%.

Entremont said it wants "milk prices at a realistic level", pointing to the falling price of dairy products such as butter, lactoserum and powdered milk.

The dispute follows this year's price de-regulation, replacing a system based on negotiations between producers, co-operatives and processors.