A top Syrian army defector will announce later on Saturday the creation of a special council that will oversee all military operations against the embattled regime of Bashar al-Assad, his media advisor told AFP.

General Mostafa Ahmad al-Sheikh, the most senior commander to defect from the Syrian army, will make the announcement in Turkey, where he sought refuge earlier this month, Fahad Almasri said in a telephone interview.

"This high military council, headed by Sheikh, will oversee military operations in conjunction with the Free Syrian Army," Almasri said.

"The council will include high-ranking officers who will plan operations to be executed by the FSA," he added. "It will also help organise defections within the army and will be in contact with officers in the regular army to encourage large-scale rather than individual defections."

The FSA, which groups Syrian army deserters, claims to have some 40,000 fighters under its command.

The government crackdown against the 10-month popular revolt in Syria has left more than 5,000 people dead according to the United Nations.

Almasri said that Sheikh, 54, defected from the army in early January along with his son and a brother, who were also in the military. Another brother who was a member of Syria's ruling Baath party also fled.

Sheikh was in charge of security matters in northern Syria before defecting.

In a statement he issued in Turkey, Sheikh said he had defected as he was sickened by the ruthlessness of Assad's regime and all the killings taking place.

"I feel your pain in the face of the murders and persecution carried out throughout the country in the last 10 months by the ruthless regime," he said in the statement addressed to the Syrian people.

He said men, women and children had been murdered by the regime which was carrying out mass killings.

"I urge all members of the Syrian armed forces, regardless of rank, to stand by the people and to forego their military oath at this historic and decisive moment," he said.