Libyan officials returned to the Egyptian capital Sunday for a third round of talks on constitutional amendments for elections. The North African nation once again finds itself at a political impasse with two rival administrations claiming legitimacy.

The talks in Cairo come on the heels of clashes between rival militias that caused residents of the Libyan capital of Tripoli to panic and revived nightmares of previous bouts of fighting in the chaos-stricken nation.

Lawmakers from Libya’s east-based parliament and the High Council of State, an advisory body from western Libya, began the U.N.-brokered negotiations amid concerted international pressure on the two chambers to put their disputes aside and agree on the election’s legal basis.

The U.N. special adviser on Libya, Stephanie Williams, said talks in a Cairo hotel will continue till June 19 with the aim of establishing a constitutional framework “required to take the country to national elections as soon as possible.”

In the previous two rounds of talks, the parties came to an initial consensus on 137 articles of the constitutional draft, including on rights and freedoms. They would continue discussing a handful of disputed articles on legislative and judicial authority, Williams said.

The dispute over the constitutional framework of the election was among major challenges that caused planned national elections to fail in December.

The failure to hold the vote was a major blow to international efforts to end decade of chaos in Libya. It has opened a new chapter in its long-running political impasse, with rival governments now claiming power after tentative steps toward unity in the past year.

On Friday, clashes broke out in Tripoli between rival militias, spurring residents to take shelter and women and children to flee a busy park as artillery shells flew across the night sky. It was not clear what cause the clashes. Authorities in Tripoli said an investigation was opened.

Williams, the U.N. adviser, condemned the fighting, saying in a Twitter post, “Enough is enough!” She called for those responsible to be held accountable.

The U.S. ambassador to Libya, Richard Norland, threatened to sanction those responsible for the fighting, saying they “will pay a price with the Libyan people and the international community.”

The violence was the latest bout of infighting in recent weeks between rogue militias, especially in the western region, which is ruled by an array of militias loosely allied with the Tripoli-based government of Prime Minister Abdul Hamid Dbeibah.

East and south Libya are controlled by forces of military commander Khalifa Hifter, who is allied with a rival government led by parliament-appointed Prime Minister Fathi Bashagha.

The oil-rich country has been wrecked by conflict since a NATO-backed uprising toppled and killed longtime dictator Moammar Gadhafi in 2011. The country has for years been split between rival administrations in the east and west, each supported by different militias and foreign governments.

AP