Residents of the Libyan capital, seat of the internationally recognised Government of National Accord (GNA), said the shelling was the worst in weeks, shaking doors and windows in the city centre several miles from the front line in the southern suburbs.

The Libyan National Army (LNA) of eastern commander Khalifa Haftar has been trying to capture Tripoli for almost a year, backed by the United Arab Emirates, Egypt and Russia. The GNA is supported by Turkey and allied Syrian fighters.

Pro-GNA forces launched an assault against LNA forces at the al-Watiya airbase, 125km (80 miles) west of Tripoli and the site of intense fighting at earlier stages of the conflict, both sides said on Wednesday.

The pro-GNA forces said their operation was in response to the shelling of Tripoli and resulted in the capture of LNA fighters. A military source in the LNA said its air force had targeted pro-GNA forces trying to capture the base.

“Violent clashes are shaking al-Watiya airbase now,” the LNA military source said.

An escalation in the fighting could spell disaster for Libya’s already fragmented and badly stretched health system in handling the coronavirus, after authorities confirmed the first case of the disease late on Tuesday.

U.N. Secretary General Antonio Guterres had called for a complete ceasefire in conflicts around the world as governments and local authorities struggle with a pandemic that has spread to most countries.

(Reporting by Ayman al-Warfalli in Benghazi and Angus McDowall in Tunis; editing by Philippa Fletcher)