ANKARA, Turkey — President Recep Tayyip Erdogan of Turkey on Wednesday approved new leaders for the army, navy and air force, in the biggest reshuffling since he won new powers for the presidency in a referendum in April.

The appointments come amid a continuing government purge of officers and civilians suspected of participating in a failed coup last year, but also as part of a longer term effort to impose civilian control over the once-dominant Turkish military.

The new appointments prepare the ground for the succession to the top military post, the chief of staff. Gen. Hulusi Akar, the current chief of staff, remains in his post, but one of the three newly appointed armed forces chiefs are likely to replace him when he retires. Usually the commander of the Turkish Army is chosen.

General Akar, who was taken hostage by rogue officers during the failed coup in July 2016, is scheduled to retire in 2019, a critical year because the changes approved in the referendum will allow the winner of the 2019 presidential election to assume full control of the government, ending the current parliamentary political system.