The European Union's top diplomat warned Monday that more intense fighting could be about to break out around the Libyan capital Tripoli, calling for a political solution to the crisis.

"Recent developments in Libya indicate that an escalation of violence around Tripoli could be imminent," said the EU high representative for foreign affairs, Josep Borrell.

The UN Security Council is to meet later Monday on the situation in Libya, where Turkish troops have begun deploying to protect the UN-recognised government from the forces of military strongman Khalifa Haftar.

On Saturday, an air strike hit a military school in the capital, leaving at least 30 people dead, according to the health ministry of the UN-recognised Government of National Accord.   

Haftar's forces denied that they were behind the attack.

"We condemn attacks such as Saturday’s strike against the military school, which only bring more violence and human suffering," Borrell said.

"Today it is more urgent than ever to work genuinely towards a political solution to the crisis in Libya," he said.

"The European Union calls on all sides to engage in a political process under the leadership of the United Nations. The European Union will continue to deploy all efforts towards finding a peaceful and political solution to this process."

The North African country was plunged into chaos with the killing of dictator Moamer Kadhafi in a 2011 NATO-backed uprising. It is now divided between the GNA and rival authorities based in the country's east.

More than 280 civilians and more than 2,000 fighters have been killed since the start of Haftar's assault on Tripoli, according to the United Nations. The fighting has displaced some 146,000 people.