The president of Zambia died Tuesday while undergoing medical treatment in London, CNN reported.

Michael Sata, known as "King Cobra" for what the news network called his "fiery comebacks and larger-than-life personality," was 77. Before he was elected in 2011, he had unsuccessfully run for the Zambian presidency three other times.

Sata was a highly visible, if not controversial, figure, and speculations about his "lack of visibility" marked his time in office, CNN added. Aides maintained that his trip to London was not due to medical reasons, even though the president felt the need last month to appear in Parliament last month merely to show he was not dead.

Although Sata liked to portray himself as a populist, the Zambian Watchdog group gave him failing grades after 18 months in power, accusing him of disobeying the constitution and lacking clear plans, Voice of America contended. It was his quick and sometimes harsh tongue, meanwhile, that earned him his nickname. In 2012, for example, he called former U.S. President George W. Bush a "young man" and a "colonialist."

Zambian Vice President Guy Scott, meanwhile, has taken over the reins of government. With that, he becomes the first white African head of state of the post-Apartheid era.

The southern African country's constitution requires presidential elections to be held within 90 days, CNN said. Scott is ineligible to permanently succeed Sata because the Cambridge-educated economist's parents were not born there, the Telegraph explained; the interim president is of Scottish descent.

Sata's 70-year-old former running mate was full of praise for the late president.

"He is called 'King Cobra' because he gets things done. He strikes. That was the origin of his name, his nickname, because he says, 'I want this done.' If it is not done, he is thumping the table the next day," Scott explained, according to Voice of America.