A silent vigil has been held for four people killed in a grenade and gun attack in Liège, Belgium.

People laid flowers and tributes to the victims, and gathered at Place Saint-Lambert at midday local time (11am EST) for a minute's silence just 24 hours after the shooting.

Students at the school where two of the victims were pupils attended the silence and reportedly joined hands in solidarity.

The BBC quoted one student, Farah el-Madane, as saying: "Life goes on, this is for sure, but it's difficult to know that it happened in Liege so you realise no one is safe."

Belgium's King Albert and Queen Paola II visited the Place Saint-Lambert on Tuesday and paid their respects to the dead.

Prime minister Elio di Rupo said there were "no words" to describe the tragedy.

"We think first and foremost of the innocent victims, their family and friends. We also think of all the people working at the scene and more generally of the people of Liege.

"The whole country shares the pain of the families affected. We share the shock of the population."

Although known as a tough, industrial city of 200,000 with a history of gun- and gang-related violence, Liège has been shocked by the attacks.

At least four people died and around 122 were injured after Nordine Amrani, 33, fired shots and threw grenades in a crowded town square in Liège.

The grenades exploded near to a Christmas market, injuring dozens and sending people running and screaming from the scene.

The dead included two teenage boys, a 75-year-old woman and a baby. The gunman was also found dead at the scene.

The attacker Amrani was known to be a "gun freak", police have said. He was convicted for five years after police found a dozen firearms in his metal workshop, including an AK-47 machine gun. He was also found guilty of drugs offences after growing 2,800 marijuana plants.

Following the attacks a dead woman was found at his home, believed to be his neighbour's cleaner.