(CNN) — A grenade and gun attack in the eastern Belgian city of Liege left four people dead, including the attacker, and at least 75 wounded Tuesday, the Liege public prosecutor said.

Those killed in the attack near a Christmas market in a city center square included two teenagers, aged 15 and 17, and a 65-year-old woman, prosecutor Danielle Reynders told reporters in Liege.

Some 52 people were treated for injuries by medics at a field hospital set up at the scene, the prosecutor said, while others went to hospitals in the area.

The attacker was identified as Nordine Amrani, 33, of Liege, Reynders said.

He died in the attack in which he hurled three grenades and fired weapons from a rooftop into the crowded square near a court building, she said.

The man acted alone in the attack in Place St. Lambert, and police are not looking for other suspects, she said, adding that he had left his home with a pistol, a semi-automatic rifle and the grenades in his bag.

Police had asked the attacker, who had been previously convicted on drugs and weapons offenses, to come in for an interview in an ongoing investigation, the prosecutor said. He had never been charged with terror offenses.

Reynders said officials were not yet able to explain the motive for the attack.

A spokeswoman for the Liege provincial governor’s office, Katrin Delcourt, told CNN that Amrani was on conditional parole but could not give details of the police investigation into him.

It remained unclear whether he had committed suicide or had died when one of the grenades exploded in his face, she said.

Oliver Moch, a spokesman for the Citadelle hospital, the largest in the Liege area, said 31 people injured in the attack had been admitted for treatment.

The Belgian Red Cross also has a team on site in Liege, operations director Gregory Jones told CNN.

“Emergency services have evacuated most victims from the site, although I can’t confirm that all have been evacuated,” he said. “We also have a team of people providing psychological support on site.”

King Albert II and Queen Paola have arrived in Liege to meet the mayor, provincial governor and workers with the Red Cross and emergency services following the attack, the Belgian royal palace told CNN.

Prime Minister Elio Di Rupo has also traveled to Liege, his spokesman said.

Liege resident Kevin Hauzeur told CNN how he ducked for cover as he heard a “huge explosion and two or three gunshots” in the city center.

A lot of people were in the area at the time to shop at the Christmas market, Hauzeur said.

The crowd was “spinning around, crying — it was really chaotic,” he said.

He said he had seen what appeared to be the body of an attacker before police cleared everyone from the area. Police told him the man had shot himself, Hauzeur said.

Charles Boisoin, whose apartment overlooks the city center, said police told him and his neighbors they could not leave their homes.

He said the city center was virtually deserted and all he could hear and see were helicopters flying overhead.

Photos purportedly from the scene, posted on Twitter by Gaspard Grosjean, showed blood on the sidewalk as well as police officers and vehicles gathered nearby.

A source close to the government, who asked not to be named because he was not authorized to speak to the media, told CNN the Internal Affairs department had been meeting to try to gather as much information as possible.

The provincial governor’s office initially said that police were searching for at least one suspect.

Liege is Belgium’s third-largest city, after Brussels and Antwerp, the national tourist office says. Dating back centuries, it is an important cultural and industrial center for the country.

— CNN’s Laura Perez Mastro, Max Foster, Jo Shelley, Samuel Burke, Aliza Kassim and Paul Cruickshank contributed to this report.