Less than a year since a landmark ceasefire, war-torn Libya is preparing for elections, but controversy over a voting law poses a new threat to the UN-led peace process.
Parliament speaker Aguila Saleh last week ratified legislation that would govern the country's presidential elections, set for December 24.
But the final version of the bill had not been presented to the assembly for a vote.
Critics charge that Saleh bypassed due process and pushed through a law favouring his ally, the eastern-based military strongman Khalifa Haftar.
They cite a clause stipulating that military officials may stand in presidential polls, on condition that they withdraw from their roles three months beforehand -- and that, if unsuccessful, they will receive backpay.
That would allow for a presidential run by Haftar, whose forces control eastern Libya, where the parliament is based, as well as parts of the south.
Haftar reached a UN-brokered ceasefire with western Libyan forces last October.
The lull in violence and a UN-led transition process have sparked hopes that Libya could move on after a decade of violence that followed the fall and killing of dictator Moamer Kadhafi in a 2011 revolt.
But analyst Khaled Al-Montasir warned that the latest move by Saleh, which bypassed state bodies in western Libya as well as members of his own assembly, could spark a return to fighting.
"The parliament can't pass a law on presidential elections on its own, especially given that there are still tensions and disputes among various parties," he said.
"There needs to be agreement over any law, given the current delicate situation."
Libya has seen months of relative peace since the October ceasefire, with a new unity government taking power early this year, charged with leading the country until the December elections.
But the UN-led Libyan dialogue forum missed a July deadline to agree on a legal framework for the polls.
"Saleh is presenting everyone with a fait accompli," said Libya expert Jalel Harchaoui.
"While his methods are problematic, he knows very well that he's filling a void."
Some Libyans, outside powers and even the UN could be tempted to accept the law, despite it being passed "on the sly and in an arbitrary manner, without a real vote", Harchaoui added.
UN envoy Jan Kubis told the Security Council on Friday that Saleh had "informed" him that "the presidential electoral law was already adopted" -- although he noted that other state bodies had complained that they had not been consulted before it was passed.
France, seen as favouring Haftar, has welcomed the law as valid, while other states have been more cautious.
President Abdel Fattah al-Sisi of neighbouring Egypt, a key Haftar backer, on Thursday "stressed the importance of the upcoming Libyan elections in respecting and activating the free will of the... Libyan people", according to a statement following a visit by Dbeibah.
Senior US official Derek Chollet, who met interim Prime Minister Abdulhamid Dbeibah in Tripoli on Wednesday, said the law was "provides a sound basis for the way forward".
"We ask only one thing of Libyan leaders: that they contribute constructively on what is on offer rather than tear it down while offering nothing instead," he told journalists.
But Harchaoui said that either scenario was likely to bolster Saleh.
"Either his methods will be rejected as invalid, and presidential elections will not be held in the coming months, meaning he remains president of parliament," he said. "Or elections will indeed take place -- but according to rules set by Saleh."