ATHENS, Greece  -- Greek authorities were investigating the serious injury of a news photographer who sustained a skull fracture after apparently being hit by riot police while covering a protest in Athens, officials said Friday.

Marios Lolos, 46, who heads the Greek Photojournalists' Association, was undergoing surgery Friday afternoon. His colleagues said a riot policeman had hit him over the head with the handle of a truncheon after the protest was over. The handles of police truncheons are made of harder plastic and therefore can cause more severe injuries.
Judicial and internal police investigations were being conducted into the incident, Public Order Minister Michalis Chrysochoidis said.

"I condemn all instances of arbitrary violence, wherever they originate from," he said in a statement.

Lolos had been covering the second day of protests sparked by the public suicide of a retired pharmacist who shot himself in the head in central Athens Wednesday morning and left a note blaming the country's harsh austerity measures for his act.

Another journalist was reportedly slightly injured in a similar protest Wednesday night. Journalists, particularly photographers and television camera crews, have frequently been targets of violence during protests in Greece, both by demonstrators and by the police.

"The systematic and repeated attacks against those in the press during their work ... cannot be considered random," the Photojournalists' Association said, adding that it could be concluded that the violence was deliberately inflicted "to muzzle the freedom of the press."

Dozens of representatives of journalists' unions also held a protest outside the public order ministry.

The police union issued a statement expressing sorrow at the injury of reporters and photographers.

"It is not possible for our union to be fighting for a modern, democratic and effective police which respects citizens and safeguards their right, and at the same time for there to be incidents such as these," it said.

Greece has seen frequent protests and riots over the past two years as its economy plunged into recession and the government imposed harsh tax increases and spending cuts, including reducing salaries and pensions, to pull itself out of a severe debt crisis.