Defying reports of an incapacitating stroke and even his death, the Libyan strongman Gen Khalifa Haftar has returned to the country from a hospital in Paris and ordered a military assault on Islamist-controlled areas.

Numerous sources has reported that Haftar, 75, had either died or had a stroke of such severity that his public career was at an end, prompting speculation that his chief backers – the United Arab Emirates, Egypt and France – were locked in secret discussions over a successor likely to play a decisive role in Libya’s future.

But Haftar’s return to Benghazi via Cairo to a triumphant reception on Thursday, and a televised statement in which he declared he was well, scotched those reports, which emanated from Paris and were largely promoted by Islamist sources. There had also been reports that lung cancer had spread to his brain.

One of Haftar’s allies said: “He was ill. He is 75, but we played along with the idea he was as ill as reported since the frenzy was to our advantage.”

Some have speculated Haftar’s allies did not do more to quash the rumours because he wanted to use the vacuum to flush out those disloyal to him inside his self-styled Libyan National Army (LNA). His absence in Paris coincided with a car bombing on 18 April intended to kill Abdulrazzak al-Nazuri, the LNA’s chief of staff.

Libya has been in political deadlock since 2014 and a UN-recognised government led by Fayez al-Sarraj, based in Tripoli, has been unable to reach agreement on the country’s future with the elected House of Representatives (HoR) based in Tobruk. The HoR is aligned with Haftar.

The new head of the state council in Tripoli, Khaled al-Mishri, and the speaker of the HoR in Tobruk, Aguila Salah Issal, met in Morocco to discuss an agreement. Although the HoR camp are confident a deal is close, the points of disagreement about power-sharing remain.

The agreement being brokered by Moroccan diplomats would reduce the membership of the Libyan Presidency Council from nine to three and lead to a unified military command across the country.

Haftar’s allies claim the LNA will now seek to capture Derna, the last eastern town out of its control, in an operation they claim may take three months. Derna, a coastal city, has been encircled by Haftar’s forces for more than a year but sporadic skirmishes have not led to a full-scale assault. Militias known as the Shura Council of Mujahideen have controlled Derna since they forced out Islamic State in 2015.

Haftr’s allies portray the LNA as a force for stability determined to root out Islamist extremists, among whom they include supporters of the Muslim Brotherhood. The LNA controls the bulk of Libya’s oilfields as well as the four export terminals in the oil crescent helping the Libyan National Oil Corporation to produce more than 1m barrels a day.

This week a former US special envoy to Libya, Jonathan Winer, portrayed Haftar as a brutal, overconfident figure more concerned with seeing off his opponents than with democracy.