Angola’s Vice-President and former CEO of state-run oil company, Sonangol, Manuel Vicente, is being considered as one of possible presidential successors, following the announcement that the current head of the country, José Eduardo dos Santos, may resign by 2018, The Oil and Gas Year reported.

President dos Santos, a Soviet-educated former petroleum engineer who has been in power since 1979 and is one of Africa’s longest-ruling leaders, officially said he intended to step down in 2018, but gave no reason for his decision, according to Reuters.

While Dos Santos did not name a preferred successor directly, some analysts suggest this succession line. “(Dos Santos) has been grooming Vicente for quite a while now. He has deputized for him on a number of important occasions, which sent a strong signal,” said Gary van Staden, a Johannesburg-based political analyst with NKC African Economics.

Other analysts claim that the President was grooming his son, Jose Filomeno de Sousa dos Santos, to succeed him. The younger Dos Santos currently heads Angola’s sovereign wealth fund.

Nevertheless, an Angola expert, Ricardo Soares de Oliveira of Britain’s Oxford University, concluded that the news of Dos Santos’ planned exit should be treated cautiously, France24 reported.

Weak oil prices have hammered Africa’s third largest economy and the government of the OPEC member country is in discussions with the World Bank and the International Monetary Fund about possible financial assistance.

Dos Santos, who oversaw the post-civil war reconstruction efforts and the period of oil- and gas-driven economic growth, was criticized for its cronyism, corruption, and unfair distribution of wealth. In 2012, Forbes magazine named him as one of the five worst leaders in Africa.

Angola holds its next parliamentary election in 2017 and the leader of the winning party is supposed to become the country’s next president.