BRUSSELS: EU investigators on Tuesday carried out raids on some of Europe's biggest suppliers of wood pulp, a key component in making paper, on suspicion that they colluded on price. Finnish paper-making giants Stora Enso and UPM said that they were investigated by the EU anti-trust teams. Both companies said they were cooperating fully with the EU regulator.

"The Commission has concerns that the inspected companies may have violated EU antitrust rules that prohibit cartels and restrictive business practices," a statement from the EU executive said.

Wood pulp is a fibrous material made from wood, which is used to manufacture different paper products including tissue, writing paper and cardboard.