The number of Islamic State group fighters in Libya has doubled to up to 6,000 in as little as a year, the head of US forces in Africa warned Thursday.
Despite the vast increase the IS group is not likely to settle and seize swathes of territory inside Libya, as it has done in Syria and Iraq, said General David Rodriguez, head of the US Africa Command.
According to the US intelligence community, about 4,000 to 6,000 IS fighters are now in the country, a number that has doubled in the last 12 to 18 months, Rodriguez said.
The Islamic State group has exploited the turmoil in Libya since the overthrow of dictator Moamer Kadhafi five years ago, raising fears that it is establishing a new stronghold on Europe's doorstep.
But Rodriguez said it is significantly harder for IS extremists to grab large areas of Libya and then consolidate.
"It's possible but right now I am not concerned about it," he said, citing "significantly different conditions" in Libya.
Among them is the fact that the IS group does not "have the homegrown people that know as much about Libya like they did in Iraq and Syria," Rodriguez said.
And the Libyan people "don't like external influences."
The IS group last year seized control of Kadhafi's coastal hometown of Sirte and has been fighting to expand to other areas.
Rodriguez said that Libyan militias "are contesting the growth of ISIS in several areas across Libya."
"In the east, in Benghazi and Derna, they have fought back against the Islamic State and made it much tougher for them to operate."
Libya has a new UN-backed unity government, which is being led by Fayez al-Sarraj, who arrived in the capital only a week ago.
Libya has had two rival administrations in place since mid-2014 when a militia alliance overran Tripoli, setting up its own authority and forcing the internationally recognized parliament to flee to the country's east.
Any possible international intervention against the IS group in Libya, Rodriguez said, "is going to be driven by their leadership and what they want us to do."