Diplomatic efforts on Libya have turned to preventing renewed violence near the strategically important coastal city of Sirte and the resource rich region known as the oil crescent beyond. Speaking at a UN Security Council session on Libya, Secretary General Antonio Guterres said a demilitarised zone could be created to prevent fresh clashes around Sirte as eastern and western factions and their international backers squared off in the centre of the country. “The conflict has entered a new phase with foreign interference reaching unprecedented levels, including in the delivery of sophisticated equipment and the number of mercenaries involved in the fighting,” Mr Guterres said. In recent months, violence has escalated in Libya after an intervention by Turkey to bolster the Government of National Accord (GNA) in Tripoli. Following a succession of victories against the Libyan National Army (LNA), led by Field Marshal Khalifa Haftar, GNA forces are now poised on the outskirts of Sirte. “GNA units, with significant external support, continued their advance eastward and are now 25 kilometres west of Sirte after two previous attempts to gain control of the city,” Mr Guterres said. “However, we are very concerned about the alarming military build-up around the city and the high level of direct foreign interference in the conflict in violation of the UN arms embargo,” he added. Sirte and Jufra to the south are the gateway to the oil crescent and a series of ports and oil terminals to the east. The eastern strip of the Gulf of Sirte is the location for four of Libya’s six hydrocarbon export terminals. More than 50 per cent of crude oil exports leave Libya through the four facilities. Restarting oil exports from Libya has been a major tranche of UN efforts to build towards a peace deal in the country. On Wednesday, Libya’s National Oil Corporation (NOC) lifted measures on the Es Sider oil terminal, to the east of Sirte, paving the way for higher oil exports from the Opec member. Despite the move, which was welcomed by the UN, Petroleum Facilities Guard forces in control of the port have continued to block a tanker from entering Es Sider. Dr Anwar Gargash, the UAE Minister of State for Foreign Affairs, addressed the Security Council calling for a ceasefire and for signatories to the Berlin Conference on Libya held in January this year to carry out its conclusions. “Six months after the conference, the UAE regrets the deterioration of the security situation in country. This downward spiral can be attributed to the continuous foreign and regional interference in Libya's internal affairs,” Dr Gargash said. The summit of world powers in Berlin sought to build on a tentative truce in Libya and find a path to peace after years of instability. In the months since, violence has increased and the principal point of progress, a recommitment to Libya’s long-flouted arms embargo, lies in tatters. The country is now more awash with arms and foreign fighters than before. Dr Gargash decried in particular the presence of 10,000 Syrian mercenaries in Libya, saying this figure was twice the number that could be found in the country six months ago. "The growing presence of mercenaries and foreign fighters exacerbates the conflict," he said. The EU’s foreign policy chief Josep Borrell spoke at the UN ahead of a European Parliament debate on Turkey’s influence in Libya and the wider region. "We all took strong commitments in the Berlin conference in January and it's now time to translate our words into concrete actions," he said. "The polarisation that has turned Libya into a theatre for proxy-war needs to stop. Action in support of one or the other Libyan parties needs to stop," the EU commissioner added. The conflict in Libya has increasingly intersected with conflicts in the wider region, drawing in European countries and fracturing Nato, pitting France and Turkey against each other. The standoff between the EU and Turkey centres on the decades-old dispute over Cyprus and the island’s frozen conflict. In December last year the GNA in Tripoli and Turkey confirmed a new maritime border deal in the Mediterranean Sea in exchange for subsequent military co-operation, which has had a profound effect on the ground in the North African nation. The UAE, Egypt, France, Cyprus and Greece condemned the agreements that would give Turkey access to potentially lucrative natural gas reserves in the area. Speaking in the European Parliament on Thursday, Manfred Weber, head of the European People’s Party, a centre-right coalition in the parliament that includes the parties of Greek Prime Minister Kyriakos Mitsotakis and Cypriot President Nicos Anastasiades, condemned Turkey’s actions in the region. “The Turkish government’s actions are currently aggravating tensions in the Mediterranean region, putting stability and security in Europe in danger,” Mr Weber said.