Johannesburg (AFP) - South Africa came under a nationwide military-patrolled lockdown on Friday, joining other African countries imposing strict curfews and shutdowns in an attempt to halt the spread of the coronavirus across the continent.

Some 57 million people are to be restricted to their homes during South Africa's three-week total lockdown which began at midnight.

Kenya, Rwanda and Mali are some of the African countries that have imposed restrictions to curb the spread of the coronavirus, which has been confirmed to have infected 3,203 people and killed 87.

Although Africa's toll is far lower than in Europe, the United States and the Middle East, health experts say the world's poorest continent is especially vulnerable and the figures likely fall far short of the reality.

Donning camouflage uniform complete with a cap, President Cyril Ramaphosa saw off soldiers before they deployed from a military base in Soweto township outside economic hub Johannesburg.

"I send you out to go and defend our people against coronavirus," Ramaphosa said.

"This is unprecedented, not only in our democracy but also in the history of our country, that we will have a lockdown for 21 days to go out and wage war against an invisible enemy coronavirus," he said.

During South Africa's shutdown there will be no jogging, dog-walking or sale of alcohol across the country, which so far has the highest number of detected infections in sub-Saharan Africa at 927, with Ramaphosa projecting it could reach 1,500 "within a few days".

Nigeria's government warned Thursday that Africa's most populous nation could soon see an "exponential" increase in infections unless contacts of confirmed cases are tracked down quicker.

- 'War against invisible enemy' -

Kenya, which has 31 cases, on Thursday recorded its first death -- a 66-year-old Kenyan man who had travelled from South Africa on March 13.

The east African country will begin a night-time curfew on Friday to try curtail the spread.

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In the Sahel, Burkina Faso, which last week recorded sub-Saharan Africa's first death, announced that eight towns, including the capital Ouagadougou, would be "quarantined" from Friday.

"Quarantined means that nobody will enter or leave the towns involved," communication minister Remis Fulgance Dandjinou said, adding that the measure would be applied for "two weeks".

In the Democratic Republic of Congo, authorities ordered a four-day "total confinement" in the capital Kinshasa, starting Saturday.

South Africans have generally embraced the lockdown.

"I think it's a good idea because if we don't go into lockdown we will lose many lives," said Sihle Mthimkulu, a 22-year-old store manager who lives in Soweto.

He works in the eastern Mpumalanga province and did not get back to Soweto in time to buy groceries for himself and his heavily pregnant girlfriend.

Mthimkulu went to a petrol station to buy bread, but there was none left, so he opted for two packets of crisps.

Earlier, panicky Johannesburg residents stocked up on food, alcohol and other supplies with some large supermarkets running out of eggs and the staple maize meal powder.

Elsewhere, thousands of people crammed long-distance bus terminals to escape to the countryside to be with families, raising fears they would transmit the virus to the most vulnerable elderly people who normally reside or retire in farms and villages.

- 'Severe financial impact' -

South Africa's Defence Minister Nosiviwe Mapisa-Nqakula warned that "if people are not complying, they (the military) may be forced to take extraordinary measures."

Violation of any of the regulations will carry a six-month jail sentence or a fine.

Two men have already been charged with attempted murder for defying a quarantine order after they tested positive for the coronavirus, exposing others to the infection.

Ditebogo Koenaite, a 27-year-old pilot, said she doubted everyone would be able to follow the rules of the lockdown.

"I think the middle class to upper class will respect the lockdown, however I don't believe that the lower class will be able to maintain social distancing," she said.

"It's harder in the more poverty stricken areas because they are sharing toilets and basic facilities."

Moody's Investors Service warned that the fallout from the border closures, commodity price declines and financial market volatility will have "severe macroeconomic and financial impact on African sovereigns".

In one early indication of the likely impact of the pandemic on Africa's economy, rubber processors in Ivory Coast -- the continent's largest producer -- said they were bracing for losses of around $100 million a month as its biggest clients in Asia, Europe and America, shut down.

"The progressive impact of this will be a slowdown in rubber processing activity, even a closedown," said Eugene Kremien, president of industry association Apromac.

"Our industry is already suffering, and it's just the start."

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