Police and troops are patrolling the capital, Maputo, following riots over high food prices  [Reuters]

Violent protests over high food prices are continuing in Mozambique, with at least seven people killed since demonstrations began on Wednesday.

Shops were looted, cars set on fire and roads barricaded on Thursday, while troops attempted to clean up streets and restore order in Maputo, the impoverished nation's capital.

Witnesses said police opened fire on protesters in a poor suburb of the city, but there were no immediate reports of deaths or injuries.

According to local television, one person drowned on Thursday after falling in a pond while escaping police.

'Irreversible' price hikes

A government spokesman said six people were killed on Wednesday, but did not give further details.

"There was heavy human and material damage and other damages, namely ... 288 wounded, 23 commercial outlets damaged and looted, 12 buses vandalised, of which one completely destroyed, and two train carriages," Alberto Nkutumula, a government spokesman, said.

He added that hikes in food prices, which sparked the demonstrations, were "irreversible".

Thousands of people have been angered by a 30 per cent increase in the price of bread and higher electricity and water tariffs.

The higher living costs are due in part to soaring wheat prices around the world due to severe drought in Russia and eastern Europe.

Mozambique also is heavily dependent on imports from South Africa, which have become more expensive in recent months as the South African rand currency has strengthened.

"I opted to join the protests because life is very difficult with these hikes, the government has turned a deaf ear to our long grievances, they only need us during election time," Teofilo Pedro was quoted by the Reuters news agency.

Unemployment in the southern African nation stands at 54 per cent, according to the government.