"Brigadier General Rodolphe Haykal was named commander in chief of the armed forces," Minister of Information Paul Morcos said after a cabinet meeting, also confirming a number of other security appointments.

Haykal, 56, was made the army's chief of operations last June, having previously served as the commander of the army sector south of the Litani River, according to the army's website.

That area bore the brunt of Israeli strikes during more than a year of hostilities with Hezbollah that ended with a November 27 ceasefire.

Haykal is expected to play a key role in the implementation of the ceasefire agreement, a security source told AFP, adding that he was Aoun's favoured candidate for the post.

According to multi-confessional Lebanon's power-sharing system, the army chief must be a Maronite Christian.

The November ceasefire required Hezbollah to withdraw north of the Litani River, about 30 kilometres (20 miles) from the border, and to dismantle any remaining military infrastructure in the south.

Israel was meant to withdraw completely from Lebanese territory by February 18, but it has kept troops at five locations it deems strategic.

Iran-backed Hezbollah, which was greatly weakened by the war, did not object to Haykal's nomination, the source said.

Morcos on Thursday also announced the appointment of the heads of the internal security, general security and state security apparatuses.

He also announced the approval of the defence ministry's request to recruit 4,500 soldiers to reinforce troops in the south, where the army is deploying alongside UN peacekeepers as part of the ceasefire agreement.