CAIRO (AP) — Libya’s rivals failed to agree on a mechanism to choose a transitional government that would lead the conflict-stricken country to elections in December next year, the United Nations said on Tuesday.

U.N. acting envoy for Libya Stephanie Williams told an online meeting for the Libyan Political Dialogue Forum that she would form an advisory committee to help bridge the gaps among the participants and “make concrete progress.”

The 75-member forum reached an agreement to hold presidential and parliamentary elections on Dec. 24, 2021. However, it failed to break the deadlock on the selection mechanism for the executive authority despite six online meetings since their face-to-face talks in Tunisia in November, Williams said.

“So far you collectively continue to struggle to agree on a way forward,” she told the attendees. “The clock is ticking, and we have a collective responsibility before the Libyan people to advance this process so as to fulfil a key objective of the roadmap, which is enabling and making a reality, the holding of the elections.”

Williams said she would announce the legal committee to work on constitutional arrangements for the elections. The committee is expected to convene Monday, before its face-to-face meeting next month, she said.

“I am fully committed, the train has left the station on this process, there is no going back ... Let’s not litigate the past. There has been a lot of litigation of the past, but we need to look forward,” she said.

Libya is split between a U.N.-supported government in the capital, Tripoli, and rival authorities based in the east. The two sides are backed by an array of local militias, as well as regional and foreign powers.

The forum is part of the U.N. efforts to end the chaos that engulfed the oil-rich North African nation after the 2011 overthrow and killing of dictator Moammar Gadhafi.

These talks took place amid a heavy international push to reach a peaceful settlement to Libya’s conflict. Previous diplomatic initiatives have all collapsed.

The warring sides agreed to a U.N.-brokered cease-fire in October in Geneva, a deal included the departure of foreign forces and mercenaries from Libya within three months.

No progress was announced on the issue of foreign forces and mercenaries since they inked the cease-fire deal almost two months ago.