At least 22 people, including a police officer, have been killed and 200 others injured in protests against a rise in the price of fuel that began on Monday, Interior Minister Manuel Homem has said.

Police say more than 1,200 people have also been arrested in what began as a strike by taxi drivers against the price hike and then escalated into one of the most widespread and disruptive waves of protest the country has seen in recent years.

Businesses, including major supermarkets, remain closed and many people have opted to stay at home.

Doctors at public hospitals in the capital, Luanda - who asked not to be named - told the BBC emergency services had been overwhelmed over the last 24 hours.

On Monday and Tuesday sporadic gunfire was heard across the city.

"We have received many protesters with serious injuries, including multiple traumas. Sadly, some have died. We fear the death toll may be higher than the official figures suggest," one doctor said.

Homem issued his statement after a cabinet meeting chaired by President João Lourenço on Wednesday.

"In the past two days, we have witnessed actions that amount to acts of vandalism and endanger public security in the provinces of Luanda, Huambo, Benguela and Huíla. However, we want to inform citizens that the overall public security situation in the country remains stable," the minister said.

Many buildings had been looted or destroyed across the country, including supermarkets, shops and banks, he added.

Ambulances, buses and private vehicles have also been damaged during the unrest.

"The acts carried out by the protesters, worsened by the presence of infiltrators with criminal intentions, show that the phenomenon has gone beyond a mere demand and now represents a threat to public order," the presidency said in a post on Facebook on Wednesday.

Earlier President Lourenço had downplayed concerns over the decision to raise the price of diesel by more than 33%. It was introduced in early July as part of plans to remove fuel subsidies in the oil-rich nation.

He told CNN Portugal the protesters were using petrol prices as a pretext to undermine the government.

The taxi unions - which called a three-day strike - have distanced themselves from the looting and destruction, stating they do not support such actions.

On Tuesday night, a flight from Frankfurt to Luanda was cancelled. A British passenger told the BBC they were told it was due to the "political situation" in Angola.

A Lufthansa spokesperson confirmed the cancellation, saying "safety and security for our passengers and crew has top priority".

Several consulates and embassies have issued security warnings to foreign nationals. The US embassy advised "US citizens to remain vigilant and limit non-essential movement within Luanda".

In the capital, long queues have formed at petrol stations as citizens try to refuel and stock up on essential goods.

Police officers are deployed across the city and there are also many military and police vehicles on the streets.

Opposition coalition the Patriotic United Front (FPU) said it stood in solidarity with "all layers of society currently experiencing the effects of the severe economic and social crisis Angola is facing".

It added this "was a result of public policies disconnected from our country's reality, poor governance, corruption and the government's lack of human sensitivity".

However, the FPU also said it "strongly condemned" the acts of destruction of public and private property carried out by protesters.

The rise in petrol prices has pushed up fares for urban Angolans who rely on taxis and has also driven up the price of staple foods and other basics - as suppliers who transport those goods by road are passing on their additional costs to consumers.