At least 392 people have been killed and 1,936 wounded since strongman Khalifa Haftar launched an offensive against the Libyan capital last month, the UN's World Health Organisation said Friday.

More than 50,000 have meanwhile been displaced as a direct result "of the intensifying armed conflict in Tripoli", according to another UN body, the Organisation for the Coordination of Humanitarian Affairs.

"We are concerned about the alarming figures of displacement," OCHA said on Friday on Twitter.

Haftar's self-styled Libyan National Army (LNA) began its offensive against the Tripoli based Government of National Accord (GNA) on April 4.

Forces loyal to the internationally recognised GNA have since launched a counter-offensive, leading to a stalemate on the ground on the southern outskirts of the capital.

Othman Abdel Jalil, the GNA's education minister and the head of the government's crisis committee, on Thursday said 55,000 people - some 11,000 families - had been displaced.

Jalil said that 40 reception centres and 27 schools had opened their doors to welcome those in need.

Most civilians who have fled the fighting have found refuge with relatives or friends, without registering with the authorities, according to humanitarian agencies.

Jalil also said that the authorities have "put in place a strategic reserve of commodities that could last for several months".