The "liberation" of Sirte and Jufra from Khalifa Haftar's forces has become "more urgent than ever" for Libya's Government of National Accord (GNA) following the deployment of mercenaries in the country, the United Nations-recognised government's army spokesperson said.
In a statement on Saturday, Muhammad Qanunu said "Sirte was the most dangerous place in Libya after it became a focal point for mercenaries of the Russian Wagner Company", who he described as "criminal gangs".
On Saturday, Libya's permanent representative to the UN called for the United States and the European Union to impose sanctions over the activities of mercenaries and other actors in Libya.
Arab League calls for Libya ceasefire, peace talks
Qanunu held Libyan parties "that have supported the rebels" responsible for the presence of Russian, Syrian and African mercenaries and their control of the oil fields in Libya.
He added that responsibility for the situation in Libya also fell on the shoulders of "Arab and foreign countries that contributed to bringing them [mercenaries] in the first place".
On Saturday, the prime minister of Libya's GNA, Fayez al-Sarraj, met with his Italian counterpart Giuseppe Conte in Rome to discuss the situation in the country and the return of Italian firms to work in Libya.
The two officials also reiterated the need for a resumption of the political process - rather than a military one – in line with decisions by the UN Security Council and the Berlin Conference.
Libya, a major oil producer, has been mired in chaos since the 2011 NATO-backed uprising that toppled and killed longtime ruler Muammar Gaddafi.
Since 2014, it has been split between rival factions based in the capital, Tripoli, and in the east, in a sometimes chaotic war that has drawn in outside powers and a flood of foreign arms and mercenaries.
Eastern-based forces under Haftar launched an offensive in April last year to try to capture Tripoli from the GNA, which is supported by Turkey.
Haftar's forces, which are backed by the United Arab Emirates, Egypt and Russia, were forced to retreat from much of western Libya in recent weeks after Turkey stepped up its support for the UN-recognised GNA.
Buoyed by their recent battlefield victories, GNA-aligned forces said they would stop their advance after retaking Sirte, a city of some 125,000 people on the Mediterranean coast and the inland Jufra airbase.
Egyptian President Abdel Fattah el-Sisi, however, warned last week that any attack on Sirte or Jufra would amount to crossing a "red line".
He said Egypt could intervene militarily to protect its western border with the oil-rich country.
In response, the GNA said it considered el-Sisi's comments a "declaration of war".
Could Egypt and Turkey go to war in Libya? | Inside Story