"There's no plan for ground troops in Libya," Obama said at a joint press conference in London with British Prime Minister David Cameron.
"I don't think that's necessary. I don't think it would be welcomed by this new government. It would send the wrong signal."
"What we can do is provide them with expertise, what we can do is provide them with training," he said.
"We can't wait if ISIL is starting to get a foothold there," he said, using an alternative acronym for IS.
The European Union on Monday offered "concrete" support to Libya's new unity government to boost the economy and security, including training for the Libyan coastguard to stem the influx of migrants across the Mediterranean.