Michael Sata arrives at Solwezi airport in Zambia before addressing supporters at an election campaign meeting on Sept. 10, 2014. (Stringer/Agence France-Presse/Getty Images)

Zambian President Michael Sata, once dubbed “Mr. King Cobra” for his sharp-tongued remarks, died Oct. 28 at a London hospital, the Zambian government said. He was 77.

The cause was not reported. Mr. Sata had traveled to London for medical treatment earlier this month.

Vice President Guy Scott, a Zambian of Scottish descent, was appointed acting president of the southern African nation until elections are held within 90 days. Scott is the first white leader of an African nation since F.W. de Klerk, the last president of South Africa under apartheid, the white racist regime that ended in 1994.

Rumors that Mr. Sata was deathly ill had gripped Zambia since the leader largely dropped out of public view months ago. Opposition groups had questioned whether he was fit to lead a country of 15 million people that has enjoyed robust economic growth but suffers widespread poverty.

On Sept. 19, Mr. Sata spoke at the opening of parliament in the capital city of Lusaka, poking fun at speculation about his failing health, saying that he was still alive. Following that appearance, he failed to give a scheduled address at the United Nations in New York, and police said doctors treated him in a hotel room. On Oct. 20, Zambia said Mr. Sata had left for a “medical check-up abroad.”

Mr. Sata had a mixed relationship with Chinese investors in Zambian mines and other infrastructure, criticizing them as exploitative but toning down his rhetoric after taking office.

Some critics said Mr. Sata became increasingly intolerant as president. An opposition leader, Frank Bwalya, was acquitted this year of defamation charges after he compared Mr. Sata to a local potato whose name is slang for someone who doesn’t listen.

As an opposition leader, Mr. Sata lost three presidential votes before becoming Zambia’s fifth president in 2011. He served in previous governments and was a member of every major party.

Mr. Sata was born in Mpika in what was then northern Rhodesia and worked as a police officer and trade unionist under colonial rule. He trained as a pilot in Russia.

After independence in 1964, he joined Kenneth Kaunda’s United National Independence Party, becoming governor of Lusaka — a city as well as a province — in 1985.

He resigned from Kaunda’s party in 1991 and joined the newly formed Movement for Multiparty Democracy, serving as a party lawmaker for 10 years and as minister for local government, labor and social security, and health.

In 2001, he left to form his Patriotic Front party. In 2008, he suffered a stroke and went to South Africa for treatment. The same year, President Levy Mwanawasa died after a stroke and a special election saw Mr. Sata narrowly lose to Rupiah Banda, who had been Mwanawasa’s vice president.

Mr. Sata and his wife, Christine Kaseba-Sata, a doctor, had eight children. Mr. Sata introduced Kaseba-Sata at the opening of parliament last month, crediting her with tough love.

“She has made me stay up to now,” he said. “I haven’t died yet.”

Associated Press