BRUSSELS, Belgium—Some 250 steel workers from Lieges ArcelorMittal plant have scuffled with police outside the prime ministers office, a day after the leading steel and mining company announced it would close seven facilities in eastern Belgium.

The workers pitched stones at police, who retaliated by using the water cannon in freezing temperatures.

Inside, Belgian Prime Minister Elio Di Rupo was assessing if anything could be done to save the 1,300 jobs at stake.

ArcelorMittal, a leading steel and mining company, blamed slumping demand for steel and structural overcapacity in Europe for its decision to close the plants.

The company said it would continue to operate five steel production lines, which employ 800 people.