The UN's envoy to Libya, Abdoulaye Bathily, announced on Tuesday that he was stepping down.
Mr Bathily said the UN could not successfully support the North African country's political transition because its leaders had put their own interests above a solution.
He was appointed to the role in September 2022 and said he had tendered his resignation to UN Secretary General Antonio Guterres. It was not immediately clear when he would leave.
The UN support mission in Libya “made a lot of efforts under my leadership over the last 18 months", but the situation has deteriorated, Mr Bathily said, condemning a “lack of political will and good faith” by Libyan leaders.
“As far as I am concerned I have done my best,” the Senegalese diplomat told reporters in New York after briefing the UN Security Council on the situation in Libya.
Mr Bathily painted a sombre picture of Libya, which has been riven by conflict and civil war for more than a decade.
He called the situation sad, as “the bulk of the Libyan population want to get out of this mess".
“Under the circumstances, there is no way the UN can operate successfully,” Mr Bathily said. “There is no room for a solution in the future.”
He said Libyans are increasingly worried for their country's future as it has become a “playground” for other nations and groups.
Russia and its Wagner mercenaries are close to military commander Field Marshal Khalifa Haftar, whose forces control eastern Libya.
Mr Bathily declined to blame specific countries and expressed concerns about parallel initiatives that undermined the UN's role.
“Concerns regarding the weakening of the international consensus on Libya are growing within the general population, as their country has become the playground for fierce rivalry among regional and international actors,” he said.
Libya is still struggling to recover from years of war and chaos after the 2011 overthrow of longtime dictator Muammar Qaddafi.
Although relative calm has returned to the oil-rich country in the past four years, clashes periodically occur between its diverse armed groups.
The country is divided between a government based in Tripoli and a rival administration in Benghazi, in the the country's east.
Mr Bathily said the renewed scramble for Libya, its position and immense resources among internal and external players is making a solution “ever elusive”.
Libyan institutional entities deliberately refuse to hold the elections seriously and are “obstinate” in postponing the vote to a date to be determined.
Mr Bathily said he urged key Libyan factions, including the Presidential Council, House of Representatives, High Council of State, Government of National Unity and the Libyan National Army, to discuss resolving issues blocking elections.
Despite his efforts, he admitted encountering resistance, unrealistic demands and indifference to Libyan interests.
The departing UN envoy said Libya's economic crisis has deepened after a decision by the Central Bank to introduce a 27 per cent tax on foreign exchange transactions, a move that was ratified by the House of Representatives on March 14.
Mr Bathily said the new policy severely limited access to foreign currencies, sparking widespread public discontent and increasing concerns over rising costs of essential goods and services, including health care.
He urged the country's authorities to “treat the disease and not just the symptoms”, of the economic malaise, describing it as a “chronic and harmful” condition.
Tarek Megrisi, a Libya expert and senior fellow at the European Council on Foreign Relations, said on X that Mr Bathily leaves Libya in a “far worse” condition than when he took his role.
Mr Megrisi said Mr Bathily's resignation could accelerate fragmentation and violence in the country.
