Associated Press (AP
) said the rioting followed days of rumours that there would be demonstrations against the increase in the bread price. Thousands of people, mainly young men, marched on the streets of Bagamoyo, a poor neighbourhood north of downtown Maputo, the palm tree-lined city, famous for its white sands and excellent fish.
Police declared the marches illegal as no permission was sought. Despite this, marches took place in other parts of the city, but apparently without serious incident.
Alice Caisane from a Maputo hospital said four of the shooting victims died there and another 16 were treated for gunshot wounds. Those killed include a young boy and a six-year-old girl on her way home from school.
Police have appealed for calm.
Violent protests erupted in the city in 2008 when food prices suddenly increased worldwide.
Mozambique is an underdeveloped country in south-eastern Africa which experienced a lengthy civil war (1977-1992) after independence from Portugal in 1975.
The country enjoys a balmy sub-tropical climate and has proven oil, gas and mineral reserves but remains one of the poorest
in the world.