The president of Angola, José Eduardo dos Santos, one of Africa’s longest-ruling leaders, announced on Friday that he would step down from office in 2018. He told the leaders of his party, the Popular Movement for the Liberation of Angola, known as the M.P.L.A., that he would resign, without elaborating, according to news reports.

It was not the first time Mr. dos Santos, 73, a Soviet-educated engineer and former guerrilla who has been in power for nearly 37 years, has pledged to leave the presidency. In 2001, as the oil- and diamond-rich former Portuguese colony was winding down a decades-long civil war, Mr. dos Santos said he would not run for re-election. He abandoned that plan. Read more on this story here.