Who is Nicolas Maduro, possible successor to Hugo Chávez?

President Hugo Chávez has named Vice President Nicolas Maduro as the heir of his self-styled socialist revolution should cancer force him out of office. He urged Venezuelans to vote for Maduro in the event of a snap election.

Here are some facts about Maduro:

* A former bus driver and trade unionist with Caracas public transport, the mustachioed Maduro, 50, has been foreign minister since 2006 and also was named vice president in October.

* As foreign minister, he has been a faithful ambassador of Chávez's views, including often radical critiques of global affairs from a hard left-wing stance.

* Maduro has won plaudits from foreign diplomats for his affable, easygoing manner. "He's the smoothest and least prickly of all the top Chávistas to deal with," one European envoy said.

* Maduro has been increasingly close to Chávez since his first cancer diagnosis in mid-2011, often at his side in Havana and giving brief updates to Venezuelans, although without giving away too many details of his boss's condition.

* Maduro's trade union background appeals to Chávez's working-class supporters and he is highly respected among the president's inner circle. Past polls have shown that opposition leader Henrique Capriles would beat him in an election but analysts say that could change in a new electoral scenario given that Maduro would have Chávez's blessing.

* Maduro was elected in 2000 as a deputy to the National Assembly, where his combative defense of Chávez's policies made him one of the president's favored proteges.

* He rose to become president of the legislature, and upon becoming foreign minister passed his previous post to his wife, Cilia Flores, a lawyer who became the first woman to serve as National Assembly president, between 2006 and 2011.

* When Chávez was sent to prison following his failed coup attempt in 1992, it was Flores who led the legal team that won his freedom two years later. She now serves as the country's attorney general. She and Maduro are seen as a "power couple" in government circles.

* Chávez' endorsement of Maduro has sidelined ambitions of other powerful Socialist Party figures such as Diosdado Cabello, who was widely considered a candidate for the top job in the future. Cabello, a military man with close ties to the armed forces and business, is not as well liked as Maduro among Venezuelans. He immediately pledged loyalty to both Chávez and the vice president after Chávez made his announcement.