DHAKA: Kurdish forces backed by US-led warplanes have recaptured a large area in Iraq near the Syrian border in an offensive against the Islamic State of Iraq and the Levant (ISIL) group, a top US commander has said.

More than 50 air strikes in recent days by coalition aircraft "have resulted in allowing those [Kurdish] forces to manoeuvre and regain approximately 100 square kilometres of ground" near Sinjar, Lieutenant General James Terry, head of the US-led campaign against ISIL, told reporters on Thursday.

Kurdish Peshmerga forces said earlier that they had captured several villages and were rolling back the ISIL fighters around Sinjar in the country's northwest, reports Al-Jazeera.

Masrur Barzani, chancellor of Kurdistan Region Security Council, said the Kurds had established a passageway to the Sinjar Mountains so that thousands of people from the country's Yazidi minority who have been trapped there can flee.

The capture of Sinjar by ISIL fighters in early August and the plight of the mostly Yazidi population there was cited by President Barack Obama as one of the reasons for the US military intervention.

The US and allied aircraft have carried out 1,361 raids against ISIL since bombing began on August 8, Terry said.

The advance of the ISIL fighters had been halted and the group was having difficulty moving and communicating as a result of the air campaign, he said.

"I think we've made significant progress in halting that progress [by ISIL]," Terry said.

In another claim of success in the battle against ISIL, US officials said on Thursday that coalition strikes have killed several of the group's senior leaders since mid-November.

BDST: 0854 HRS, DEC 19, 2014