The situation was still "tenuous" but for the moment, Kurdish forces were holding their ground and US air strikes had slowed the momentum of the IS group, Rear Admiral John Kirby told reporters.

"The situation in Kobane still remains tenuous. We do assess that Kurdish forces in the city are in control of the majority of the city," Kirby said.

"That said, ISIL (Islamic State group) forces continue to threaten it" and still had fighters in "some strength" in parts of the town, he said.

"We've been watching this now for weeks. Certainly in the last several days at least, we know ISIL hasn't made any progress inside Kobane," he said. "But it can change."

US aircraft kept up raids overnight in support of the Kurds, after American C-130 cargo planes dropped ammunition and medical supplies to the Kurdish forces early on Monday. The small arms and ammunition were provided by Kurdish authorities in Iraq.

Kobane, located near the Turkish border, has become the focus of world attention and turned into a high-stakes symbol in the war against the IS group. The Sunni extremists are fighting to expand areas under their control in Iraq and Syria while a US-led coalition is carrying out air raids in a bid to halt their advance.