The militants are taking advantage of the chaos that grew after Libyan leader Moammar Gadhafi was ousted and killed in a 2011 revolution as well as a declining Western presence in the country.
U.S. plans to help rebuild Libya after Gadhafi largely fell to the wayside amid growing violence and the 2012 terror attack on the U.S. diplomatic facility in Benghazi that killed U.S. Ambassador Chris Stevens and three other Americans.
The Islamic State, also known as ISIL or ISIS, has taken up residence in the coastal city of Sirte and is attempting to expand its influence in Libya.
“The worrisome thing is if ISIS central decides to pivot and pour more resources in, it could be worse," said Frederic Wehrey, an analyst at the Carnegie Endowment for International Peace.
The militants seem to be pressing south and east of Sirte to control oil facilities in the area, he said.
“Libya is probably right now the most significant threat to becoming a full-blown sanctuary” for the Islamic State, said Patrick Johnston, a counterterrorism analyst at RAND Corp.
The Islamic State's expansion comes as U.S. efforts to build a unified government in Libya have declined.
The United States acknowledged last year that it suspended efforts to train a Libyan force of 5,000 to 8,000 personnel, as fighting escalated among warring factions and because the country lacked a broad-based government, according to the Pentagon.
The United States is continuing to pursue diplomatic efforts to create a unified government there. Read more: