BRUSSELS -- Belgian police fired tear gas and water cannon at ArcelorMittal (IW1000/35) workers who hurled paving stones and iron bolts across barriers during a tense protest in southern Namur on Tuesday that marked an escalation of their battle to save their jobs.

Five officers were injured in the clashes, including one who was hospitalized, police and local authorities said following a protest that gathered between 1,200 and 1,500 angry steelworkers, according to police and unions.

The company later said that it was working with those who are set to lose their jobs -- some 1,300 in Belgium -- to find a "socially acceptable solution."

"We were stunned by the violence with which some of the protesters attacked us," said local police chief Pascal Ligot.

He said baseball bats, iron rods and bolts were used as weapons in the skirmishes at one of the plants earmarked for closure.

"They went straight to attack, without hesitation, without any chance of dialogue," he said.

Stones smashed windows in nearby shops although there were only light injuries among protesters as they were shepherded behind barricades, the Belga news agency reported.

The new unrest followed a clash outside Prime Minister Elio Di Rupo's official residence on Friday, when police fired water cannon and pepper spray at several hundred workers hurling firecrackers, rocks and bottles.

Unions, who have mounted a series of protests at doomed sites, said in Namur that they will next target ArcelorMittal's headquarters in Luxembourg and the European Parliament in Strasbourg, although they did not specify dates.

"We're going to pressure the politicians -- it's up to them to make Mittal fold," said one union representative, David Camerini.

ArcelorMittal is shutting down six cold-processing facilities in the Liege region of eastern Belgium, blaming weak demand for cars and cutbacks in auto plants for the fall in demand for steel.

The company is also embroiled in controversy in France over the closure of two blast furnaces.

The company reacted Tuesday evening with a statement saying that despite being "well aware" of the strength of feeling at its "difficult" decision, the group "refuses to sanction violence."

It added, however: "ArcelorMittal is committed to working with its staff to find a solution that is socially acceptable to all those impacted by this (decision)."

In Belgium, in an echo of other once-powerhouse industries such as coal and shipbuilding, the numbers employed in the steel business collapsed from some 34,000 in 1981 to under 10,000 this year.

Copyright Agence France-Presse, 2013