The UN’s special representative for Libya has said the country’s warring sides are working to turn a provisional ceasefire into a formal agreement as they emerged from four days of talks. Ghassan Salame, head of the United Nations support mission in Libya, said rival military leaders are negotiating the remaining sticking points in a ceasefire deal.

Salame said delegates will reconvene Friday to discuss the latest draft, AP reports. That agreement must then be sent back to their respective leaders for approval.

The return of internally displaced people, the disarmament of armed groups, ways to monitor a truce and how to deal with heavy weaponry are among the unresolved issues.

The latest round of fighting erupted last April when eastern-based forces under the command of Khalifa Hiftar laid siege to Tripoli in a bid to wrest power from the UN-backed government. The rivals sent delegations of military officials to represent them at the Geneva talks.