A lone gunman who went on a murderous spree in the Belgian city of Liege committed suicide after slaying three youngsters in a crowded square and killing a cleaning-woman, the prosecutor said on Wednesday.

"Nordine Amrani committed suicide with a bullet to the head," said Daniele Reynders at a press conference. "The coroner said he shot himself in the forehead. He left no message to explain his act."

A lone gunman armed with grenades opened fire on a square packed with children and Christmas shoppers in the eastern Belgian city of Liege Tuesday, killing three people and wounding 75.

Officials named the gunman -- who was himself also killed in circumstances that are not yet clear -- as Nordine Amrani, 33, a known criminal who had been summoned by police that morning but who never showed up.