ROME — The "other" front line in the war against ISIS is in Libya.

An ongoing civil war has created fertile ground for the Islamist terror group to expand four years after the fall of longtime dictator Muammar Gaddafi. Settling differences between two rival governments in the capital of Tripoli and the eastern city of Tobruk is key to shutting down the rapid expansion of ISIS in the North African country.

A lasting solution to the conflict between the internationally recognized government in the east — supported by Egypt — and the Qatar-backed parliament in Tripoli is critical to tackling the increasing terror threat.

Along with the United States, Italy is pushing a new diplomatic strategy that will be put to the test Sunday at an international conference in Rome on the Libyan crisis. Diplomats have made it a priority to bring Egyptian President Abdel Fattah al-Sisi into the fold. U.S. Secretary of State John Kerry and Italian Foreign Minister Paolo Gentiloni have invited at least 15 countries to participate in the talks, which the Obama administration plans to model on the recent Syrian peace talks in Vienna. Ahead of the meeting, the UN called on world leaders to contribute more than $160 million to help Libya recover from years of conflict, the AFP reported Thursday.

Among the countries invited to Sunday's summit are the five permanent members of the United Nations Security Council — the U.S., Russia, France, the UK and China — as well as Italy, Germany and Spain. Representatives of seven Middle Eastern and North African countries — Algeria, Tunisia, Qatar, Egypt, Turkey, Morocco and the U.A.E. — will also be present in Rome, along with European Union foreign policy chief Federica Mogherini and UN Special Envoy to Libya Martin Kobler.

The goal is to reach an international consensus around a UN peace plan to establish a united government supported by both parliaments — to be based in Tripoli, and led by a member of the government in Tobruk.

Though representatives of Libya's warring parliaments recently reached their own peace agreement at a meeting in Tunis, months after rejecting the UN-backed deal, it is not clear if the deal will stick. The Tunis agreement calls for the two sides to establish a committee to nominate a prime minister and another to review the constitution, before holding elections.

Cairo's role

Washington and Rome are betting that the urgent need to face the stronger ISIS presence in Sirte, Libya, will accelerate the peace process to end the civil war between the Islamist militias in Tripoli and the government in Tobruk. Though the Pentagon confirmed reports this week that Libya's top ISIS leader Abu Nabil was killed during a U.S. airstrike last month, the jihadist group continues to expand.

Italian Foreign Minister Paolo Gentiloni (center) is trying to cool the Libyan crisis — Photo: Luca Marfe

Diplomatic sources note that any lasting solution will require an accord between Qatar and Egypt, the primary foreign backers of the two sides.

Cairo is concerned that placing the national unity government in Tripoli would give excessive influence to the Islamist militias that control the capital. Instead, Egyptian diplomats have proposed a "third location" for the new government, somewhere in Libya or perhaps even abroad.

Egyptian President Sisi is pursuing closer ties with Russia and the Tobruk government has taken notice, with some members advocating a Russian intervention modeled on President Vladimir Putin's actions in Syria. Moscow hasn't had a military role in Libya since 2011, when it was expelled after a NATO air campaign led to the collapse of Gaddafi's regime.

"Egypt's priority is to maintain the role of General Khalifa Haftar's forces in Tobruk," says a source in Cairo. "They consider him indispensable to protecting Egypt from jihadist infiltration."

Italy also recognizes Moscow's key role in negotiations on the Libyan crisis, which Gentiloni discussed in a recent meeting with Russian Foreign Minister Sergei Lavrov. As for Italy's European allies, the UK and France support the U.S.-Italian peace initiative in Rome, but British sources stress that a military option to strike ISIS bases in Libya must remain on the table.

Air strikes in Libya, potentially bolstered by special forces to carry out targeted operations against bases and leaders, would extend the anti-ISIS campaign already underway in Syria and Iraq. In the best case scenario, the negotiations in Rome will learn from the mistakes in Syria, and be sure they are not repeated in Libya.