ISTANBUL/TRIPOLI－Turkish President Recep Tayyip Erdogan said on Sunday that Turkey is "gradually" sending troops to Libya under a deal inked with Libya's United Nations-recognized Government of National Accord, or GNA.

"Our soldiers are gradually going," Erdogan told the CNNTurk broadcaster in a televised interview.

"The duty of Turkish soldiers is to ensure the ceasefire and not to fight. What we will do in Libya is to strengthen the legitimate government," he added, noting an operation center would be established in the North African country torn by a raging civil war, which pits the GNA based in the capital Tripoli against the Libyan National Army, or LNA, and its allies based in the east.

The mission for Turkish troops in Libya is to oversee coordination at the operation center, said the Turkish leader.

"As an opposition force, we will have different teams there," he added.

The Turkish parliament on Thursday passed a motion authorizing the government to deploy troops to Libya in support of the GNA, as Ankara signed security and military cooperation agreements with it as well as a controversial maritime boundary memorandum at the end of November.

The Turkish move has prompted opposition from some of its regional neighbors, while Libya's elected parliament, the GNA's rival in the war, voted on Saturday to sever ties with Turkey.

The UN Security Council was expected to meet behind closed doors on Monday about the situation in Libya, diplomats said on Sunday. The meeting, held at Russia's request, is formally focused on an international conference on Libya that Germany hopes to organize by month's end. So far, no date for the meeting has been announced.

But Monday's talks were the first chance for Security Council members to discuss controversial security and maritime deals struck by Libya and Turkey－and Ankara's subsequent decision to send troops to Libya.

On Friday, UN Secretary-General Antonio Guterres renewed his call for an immediate ceasefire in Libya.

Forces of the GNA on Sunday announced the launch of a deadly airstrike on an air base of the rival army located nearly 140 kilometers southwest of Tripoli.

A Turkish drone targeted al-Watia air base, killing three army soldiers and injuring six others, said TV channel Al-Hadath, showing footage of wounded soldiers being treated in a hospital.

Mohamed Gonono, spokesman of the GNA's military forces, said targeting the air base came in retaliation for a deadly airstrike on Saturday on a military academy in Tripoli.

Thirty students were killed and 33 others were injured in the airstrike according to the Ministry of Health of the GNA.

"Our forces targeted positions of (LNA leader) Khalifa Haftar's militias in al-Watia air base, destroying military vehicles, an ammunition store and mercenary gatherings," Gonono said in a statement.

The LNA had denied responsibility for the airstrike on the military academy.

"The General Command (of the army) completely denies responsibility for bombing the military academy in Tripoli," spokesman of the army Ahmad al-Mismari told a news conference in the eastern city of Benghazi.

"The bombing of the military academy could be the result of a motor shell, not an airstrike," the spokesman said.

Mismari said that an official investigation has been started, calling on the UN to send a committee to help investigate details of the attack.

The LNA has been leading a military campaign in and around Tripoli since early April, trying to take over the city and topple the UN-backed government.

Thousands have been killed and injured in the fighting, and more than 120,000 people fled their homes from the violence.