Zambia's President Michael Sata -- nicknamed "King Cobra" for his sharp tongue and manner -- has died, officials said Wednesday, making his vice-president Africa's first white head of state in decades.
Sata, 77, died Tuesday while undergoing treatment in London's private King Edward VII hospital for an unspecified illness, the Zambian government said.
Vice-President Guy Scott, 70, was named interim leader -- making him the first white president of an African nation since FW de Klerk ruled apartheid South Africa more than 20 years ago.
Scott, whose parents were from Scotland, is not eligible to stand in the upcoming presidential election -- which must be held within the next 90 days -- because of a rule in Zambia's 1996 constitution barring heads of state with foreign parents.
"Dr Scott will act as president of the Republic of Zambia until the country goes for a presidential by-election" said Defence Minister Edgar Lungu.
Scott issued a statement confirming his temporary promotion and the 90-day period for the elections.
He added that national mourning for Sata would begin Wednesday. "We will miss our beloved president and commarade," he said,
Sata was elected in 2011 to preside over his landlocked, southern African nation of 15 million people.
It was a triumphant post for a man who rose from sweeping London railway stations, through to being a policeman and trade unionist.
Once in power, though, he proved to be an authoritarian populist who inveighed against political foes, the media and sometimes even allies, earning him his snakey sobriquet. His admirers saw him more as a no-nonsense man of action.
Rumours of him being seriously ill persisted during his final months in office. Frequent denials by the government -- and legal action against activists claiming he was dying -- did nothing to dispel them.
Sata had not been seen in public since returning from the UN General Assembly last month, where he failed to make a scheduled speech.
The announcement by cabinet secretary Roland Msiska on Wednesday that Sata had died created little surprise.
"It is with a heavy heart that I announce the passing on of our beloved president," Msiska said in an address to the nation.
Speculation was turning to who might become Zambia's next president.
Even before Sata's death, analysts had said a power struggle for Zambia's top job was already well under way within the ruling Patriotic Front (PF) party.
When Sata flew to London just over a week ago for treatment he appointed his defence minister as acting president.
But Lungu, who also holds the justice portfolio, is seen as just one of several potential candidates within the faction-ridden party.
And outside the PF, former president Rupiah Banda, who is facing graft charges, has hinted at a possible return to active politics.
"I am legally eligible to stand," he told AFP early this month, citing calls from his supporters to return to the political fray.
African leaders meanwhile paid tribute to Sata.
Kenya's President Uhuru Kenyatta hailed him as an "outstanding son of Africa".
"He was gifted with unique, admirable abilities and strong values," Kenyatta said in a statement.
South Africa's ruling ANC said: "Zambia has lost not only a president who prioritised the poor, but also led the Zambian government at a time when the continent is working to reclaim its place in the global governance and economy."
Sata rode to power on the back of resentment against the Chinese resource firms that dot Zambia, describing them as "infesters".
His government had recently cracked down on political opponents and critical journalists who reported on his long-suspected illness and frequent "working trips" abroad, apparently for medical treatment.