Bamako (AFP) - Four countries led by war-ravaged Mali on Wednesday joined the lengthening list of African countries hit by the novel coronavirus as Kenya ordered a curfew and unveiled tax breaks in the fight against the pandemic.

Mali, mired in an eight-year-old conflict, said two nationals who had returned from France had tested positive for the virus.

Libya, another conflict-torn country, as well as the volatile West African state of Guinea-Bissau and Uganda in East Africa also reported their first cases of COVID-19.

More than 2,400 cases were recorded in all of Africa as of Wednesday, according to an AFP tally, with 64 deaths.

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 to the virus and the figures likely fall far short of the reality.

"We must prepare for the worst (because) we have no idea of the scope of the propagation" in the Democratic Republic of Congo, 2018 Nobel Peace laureate Denis Mukwege said Wednesday.

Mukwege called for "large-scale" testing across the vast former Belgian colony of 80 million inhabitants, which reported 48 cases of COVID-19 as of Tuesday, with three deaths.

Poor healthcare infrastructure, weak governance and crowded slums present ideal conditions for the respiratory disease to spread.

Conflict, in particular, is a major factor in aggravating the risk.

Mali is struggling to contain an Islamist insurgency that erupted in the north in 2012 and has since claimed thousands of military and civilian lives.

The government earlier banned commercial flights from virus-stricken countries.

The UN on Wednesday put the spotlight on the Central African Republic (CAR), also gripped by conflict.

CAR "is one of the least prepared countries to face a COVID-19 outbreak, with 2.2 million people already in need of health assistance and about 70 percent of health services provided by humanitarian organisations," the country's coronavirus Global Humanitarian Response Plan warned.

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- Pay cut for Kenyatta -

Kenyan President Uhuru Kenyatta meanwhile ordered a nighttime curfew to curb the spread of the coronavirus, while taking a massive pay cut and unveiling tax breaks to ease the economic impact of the crisis.

In a lengthy address to the nation, Kenyatta warned he would not hesitate to take "more drastic measures" if Kenyans did not make efforts to limit the spread of the virus, which has sickened 28 in the country.

African states have been adopting increasingly restrictive measures against the invisible peril.

Senegal and Ivory Coast have declared states of emergency and ordered nighttime curfews, similar to South Sudan, which has ordered a nightly lockdown from 8:00 pm to 6:00 am.

South Africa, the continent's largest economy, is set to enter a lockdown from Thursday.

Ethiopia announced Wednesday it would free more than 4,000 prisoners to help prevent an outbreak in overcrowded prisons.

The measures will apply to those jailed for "petty crimes" and drug offences or have less than a year remaining on their sentences.

Conditions in Ethiopia's prisons are "harsh and in some cases life-threatening," marred by "gross overcrowding and inadequate food, water, sanitation and medical care," according to the latest annual human rights report on Ethiopia from the US State Department.

- 'Panic mode' -

In the Nigerian capital Abuja, meanwhile, fears spread of coronavirus infection among senior politicians.

A number of state governors as well as Vice President Yemi Osinbajo were in self-isolation after coming into contact with two individuals infected with COVID-19.

According to the president's office and local media, one of them is President Muhammadu Buhari's chief of staff, Abba Kyari, one of Nigeria's most influential figures.

The political elite "is in panic mode following the confirmed case of the chief of staff,"a source close to the presidency said.

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