Kazakhstan's President Nursultan Nazarbayev, who has led the country since independence from the Soviet Union, has announced his resignation. In a televised address, he said the decision had "not been simple" but gave no reason for the move.
Mr Nazarbayev, 78, has been largely unchallenged since he became leader of the oil-rich nation in 1989. He has focused on economic reform while resisting moves to democratise the political system.
"I have decided to give up my powers as president," he said during the surprise address.
Mr Nazarbayev said the speaker of the upper house of parliament, Kassym-Jomart Tokayev, would take over as acting president for the remainder of his term which expires in March 2020. He had been widely expected to seek re-election and has never indicated a successor.
Last May, Mr Nazarbayev became lifelong head of Kazakhstan's influential security council. He will remain in this role and continue as head of the ruling Nur Otan party. He will also hold the formal title Leader of the Nation.
The announcement comes just weeks after the leader sacked the country's government, citing failures to improve the economy.
"In many areas of the economy, despite the adoption of many laws and government decisions, positive changes have not been achieved," he said in a statement at the time.