ROME -- Nations fighting the Islamic State of Iraq and Syria (ISIS) discussed Tuesday how to prevent the extremist group from gaining a stranglehold in resource-rich Libya, though no one appeared resolved just yet to launch a second military intervention in the North African country this decade.

Speaking at a 23-nation conference in Rome, U.S. Secretary of State John Kerry said the last thing anyone wants "is a false caliphate with access to billions of dollars in oil revenue." He said the U.S. and its European and Arab partners should increase security training and help Libya's military "not just to clear territory, but to create a safe environment for the government to stand up and operate."

More than four years after a U.S.-led military effort helped topple dictator Muammar Qaddafi, Libya is mired in chaos. Since 2014, it has been split between two rival authorities. A new unity government still doesn't have parliamentary approval.

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Amid the chaos, an ISIS affiliate has carved out territory in the center of the country and fighters, wearied by coalition airstrikes in Iraq and Syria, are flocking to the new front.

The group is based in the northern coastal city of Sirte. It is estimated to have somewhere between 2,000 and 5,000 fighters there.

Last week, U.S. Defense Secretary Ash Carter warned that ISIS militants were trying to "consolidate their own footprint" in Libya by setting up training sites, drawing in foreign recruits and using the levers of economic power to raise money through taxes.

Libya, due to the relative lawlessness of its borders, its close proximity to Europe and the fact that it serves as a major disembarking point for the human traffickers who send thousands of migrants and refugees toward Italy every month, is of particular concern. There have been fears voiced by officials in Europe for at least a year that ISIS could try to get militants aboard the boats that land in Italy.

A report Monday in the Telegraph newspaper of Britain, meanwhile, said ISIS is aggressively recruiting new members in Libya from among the throngs of Middle Eastern and African migrants traversing the nation, offering bonuses of $1,000 to new recruits.

The newspaper cited the head of military intelligence in the Libyan city of Misurata, Col. Ismail Shukri, as saying as many as 70 percent of ISIS' fighters in Sirte now are non-Libyan.

"The majority -- I cannot tell you exactly how many -- are Tunisians, while the rest are made up mostly of Sudanese, Egyptians and then people from the Sub-Saharan countries stretching from Chad and Nigeria, along with a few from Algeria and the Gulf," he told the Telegraph.

"Sadly, we have big open borders and long open areas, and through the routes for illegal immigration, we now have all this ideology coming through. That is one of the reasons why Isil has come to Libya," Shukri said.

The U.S. won't allow ISIS to "sink roots" in Libya, Kerry said, but provided no indication of any U.S. military campaign was imminent.

European countries, too, are weighing options.

Italy, whose southernmost territory is less than 300 miles from Libya, has indicated it would participate in a U.N.-authorized peacekeeping or stabilization mission. It has moved aircraft to a base in Sicily, but insists that any action first requires a stable Libyan government and other international assistance. The instability has led to hundreds of thousands of migrants using Libya-based smugglers to reach Italy.

"We cannot imagine spring passing with the situation in Libya still stalled," Defense Minister Roberta Pinotti told Italy's Corriere della Sera paper last week. Britain and France also are considering military possibilities, with similar caveats.

A senior U.S. official attending the talks stressed that "when we see a threat to the United States or external plotting, we will not hesitate to act upon that threat." He cited a November airstrike that that killed Abu Nabil, a top ISIS leader in Libya.

But any broader campaign would require talks with coalition partners and the Libyans, said the official, who briefed reporters on the discussions on condition he not be quoted by name. He said President Obama convened a National Security Council meeting last week "focused on the Libya question."