Turkish Prime Minister Recep Tayyip Erdogan has opened a crucial meeting to decide on key military appointments, after the country's top four military commanders resigned last week.

Mr. Erdogan Monday launched the four-day annual meeting of the Supreme Military Council in Ankara. He sat alone at the head of the table where normally he would have been joined by the chief of staff.

Long-running tensions between the secularist military and the Islamist-oriented government came to a head Friday when the chief of Turkey's military forces, General Isik Kosaner, and the army, navy and air force commanders stepped down to protest the arrest and prosecution in recent years of hundreds of military officers in alleged coup plots.

This is the first time the annual meeting is being held without Turkey's top four generals attending. Afterward, the prime minister accompanied the generals in a traditional wreath-laying ceremony at the mausoleum of Mustafa Kemal Ataturk, the founder of modern Turkey.

In Washington, Admiral Mike Mullen, chairman of the U.S. Joint Chiefs of Staff, said it is an internal issue for Turkey, and there appeared to be an orderly transition. He said he saw no indication that the U.S.-Turkish military relationship has been affected.

Turkish President Abdullah Gul told reporters Saturday in Ankara that the resignations were “extraordinary,” but he said there will be no power vacuum.

The government moved quickly to appoint General Necdet Ozel, chief of the gendarmerie, as head of the army and acting chief of general staff.

Friday's resignations came after General Kosaner met with Prime Minister Erdogan and President Gul to discuss key promotions of military staff at Monday's council meeting. Mr. Erdogan is reported to have indicated he would block promotions for officers he believed were part of a conspiracy to bring down his government.

Turkish authorities have detained more than 300 people as part of a wide-reaching investigation into alleged plots to undermine the government. About 200 active and retired military officers, including 30 generals, have been charged in the probe. Most of the officers who have been charged are being held in prison.

The Turkish army has forced four governments from power since 1960.