President Malam Bacai Sanha, who was elected in this tiny, coup-prone nation on Africa's western coast about two years ago after the previous leader was assassinated, died Monday in Paris after a lengthy hospitalization.
No immediate cause was given but the 64-year-old president was known to have diabetes, and had undergone medical treatment in both France and neighboring Senegal during his time in office. National radio announced his death Monday afternoon.
An official at Guinea-Bissau's embassy in Paris, Luis Mendes, said Sanha died Monday morning at the Val de Grace hospital after being hospitalized in France "for about a month" with an unspecified ailment, Mendes said.
The head of the National Assembly, Raimundo Pereira, is again expected to take over until new elections can be organized. He already has served as interim head of state after the 2009 assassination of former President Joao Bernardo "Nino" Vieira.
Officials declared seven days of mourning. They did not say when elections might be held.
Since independence from Portugal in 1974, the nation has been wracked by coups and has become one of the main transit points for drug traffickers ferrying cocaine to Europe. Just two weeks ago, the army said a top military official had attempted unsuccessfully to seize power while Sanha was ill.
Sanha won the 2009 presidential election held after Vieira's death, a peaceful transition of power that marked a rare bright spot for Guinea-Bissau. He became less known for what he did as president than for his frequent hospitalizations abroad, which were always described by aides as routine checkups.
In August 2009, he spent nearly three weeks hospitalized in Dakar, the capital of neighboring Senegal, where medical facilities are better equipped than in Bissau.
A diplomat said at the time that the president had become a regular visitor in Dakar, arriving on a special flight each time his blood sugar was out of balance. And a veteran observer with close ties to the president's entourage described the illness as "advanced diabetes" combined with a hemoglobin problem.
United Nations Secretary General Ban Ki-Moon paid tribute to Sanha's leadership, noting in a statement that he guided Guinea-Bissau "at a particularly difficult time in its history."
"The Secretary-General trusts that the succession arrangements provided for in the constitution of Guinea-Bissau will be fully respected," Ban's spokesperson said in a statement.
Sanha began his political career as the head of the youth wing of the African Party for the Independence of Guinea and Cape Verde, or PAIGC _ the body that fought for the country's independence from Portugal in 1974. He went on to become a member of its executive committee, and then served as a governor of a province.
Sanha was thrown to the fore after Vieira's March 2009 assassination, when the president was gunned down inside his home. Pereira became interim head of state until elections were organized, which Sanha won.
The circumstances of Vieira's death have never been fully illuminated, but many speculated that his killing was related to issues surrounding drug trafficking.
In recent years, Guinea-Bissau has become a hub for drug smuggling. Cocaine flown in from South America to the archipelago of islands that dot the country's coastline. The drugs are then moved to Europe by boats and by mules who ingest the drugs and attempt to carry them north on commercial flights. Sanha had pledged to combat the flow of narcotics.
"Drug trafficking must end in this country," he told a meeting of top military officials in July.
Nevertheless, he appointed Jose Americo Bubo Na Tchuto, labeled by the U.S. Treasury Department as a drug kingpin, to head the Navy in early October.
"You must prove to those who accuse you of being steeped in illicit activities that what they say does not correspond to the truth," Sanha said at Na Tchuto's induction ceremony.
Carlos Vamain, a political analyst and former justice minister, called Sanha's presidency difficult and complex.
"Difficult in the context of narco-trafficking and also the unchanging socio-economic problems of the country," Vamain said. "His presidency did not bring the results people had hoped."
Associated Press writers Angela Charlton in Paris, Rukmini Callimachi and Artis Henderson in Dakar, Senegal and Michael Astor at the United Nations contributed to this report.