Belgian officials say four people have died and at least 64 others were injured in an attack in the eastern city of Liege.

Reports from the scene say a lone gunman lobbed hand grenades and opened fire at a bus stop in Saint Lambert Square, a busy area in Liege.

Officials say the gunman was among the four dead. Earlier reports said several assailants were involved.

Police sealed off the area as emergency rescue teams responded to help the victims of the attack.

Authorities have not yet said what might have motivated the attacker.