BRUSSELS, June 4 (Xinhua) -- Some 300 fishermen from France, Italy and Portugal demonstrated against soaring marine fuel prices throughout Wednesday in Brussels, clashing with Belgian riot police at one stage and breaking some windows of the European Commission's building.

    The demonstration started around 9 a.m. (0700 GMT), with the protestors setting off flares and smoke canisters, waving flags and chanting slogans.

    The price of marine diesel has soared over the last year, with prices now at around 0.80 euro a liter. The fishermen were demanding a discounted rate of 0.40 euro a liter.

    The demonstration forced the police to seal off several roads, including the Archimede street outside the Xinhua bureau, causing traffic jams in the EU quarter of Brussels.

    Violence flared in the early afternoon after a delegation of around 20 fishermen returned to the crowd following a hastily arranged meeting with officials from the office of EU fisheries commissioner Joe Borg.

    The demonstrators fired flares, damaging the European Commission's Berlaymont headquarters and breaking windows in several nearby buildings.

    Riot police used water cannons vehicles in an attempt to disperse the crowd. But the demonstrators responded by overturning at least one car and setting fire to dustbins.

    The demonstrators disassemble in the late afternoon, but policemen were still on alert outside the European Commission and EU Council buildings in the early evening.

    The demonstration in Brussels followed similar protests in London and Paris on Tuesday.