The leader of Yemen's southern separatists has warned against the looming collapse of a power-sharing deal, saying the region is menaced by the twin threats of economic catastrophe and Islamist attacks.

Egypt has accused four staff of Turkey's state news agency Anadolu whom it arrested of spreading "false news" and working with the outlawed Muslim Brotherhood group.

Dozens of fighters and civilians were killed in Syria's Idlib province as the government pressed a deadly offensive Thursday towards a key town in the country's last rebel bastion.

Turkey said Wednesday it was still confident the ceasefire in Libya would hold despite strongman Khalifa Haftar's refusal to sign a permanent truce.

Haftar walked away from talks in Moscow aimed at finalising a ceasefire orchestrated by Russia and Turkey, which came into force Sunday.

The EU's diplomatic chief has admitted the bloc is struggling to influence the Libyan conflict and has left Russia and Turkey free to step in and dominate the Mediterranean.

Israel carried out an aerial attack that damaged a military airport in central Syria, according to a military source quoted by Syria's state news agency.

An American citizen whose case was raised by top US leaders died Monday after more than six years in custody in Egypt, his representatives said, drawing criticism by Washington of its authoritarian ally.

Mustafa Kassem, a New York taxi driver originally from Egypt who was arrested on a home visit in 2013, had been on a liquid-only hunger strike since last fall and four days ago ceased drinking fluids.

Turkish President Recep Tayyip Erdogan said on Tuesday he would "teach a lesson" to Libyan strongman Khalifa Haftar if he resumed fighting after abandoning ceasefire talks in Moscow.

Russia will continue pushing for a ceasefire agreement in Libya, Foreign Minister Sergei Lavrov said on Tuesday, after strongman Khalifa Haftar left talks in Moscow without signing a deal.

Libya's eastern strongman General Khalifa Haftar has left Moscow without signing a ceasefire agreement to end nine months of fighting in the country, the Russian foreign ministry confirmed to AFP Tuesday.