Authorities in Portugal have opened an inquiry into incidents during an anti-austerity protest when two press photographers were injured during a police charge.

About 150 people marched in downtown Lisbon late Thursday to oppose government debt-reduction measures adopted in return for the country's (EURO)78 billion bailout last year.

Some of them threw glasses and bottles at police. The Portuguese Journalists' Union alleged police struck photographers with domestic news agency Lusa and Agence France Presse with batons during an ensuing charge.

Video showed police hitting the Lusa photographer while he was on the ground and shouting he was with the press.

The Interior Ministry, which oversees the police force, announced Friday it had ordered an inquiry.