By Michelle Nichols
UNITED NATIONS, Aug 11 (Reuters) - Thousands of people from Iraq's Yazidi minority trapped on a mountain in northern Iraq by Islamic State militants have been able to escape in the past three days with help from Kurdish security forces and others, a U.N. official said on Monday.
Kieran Dwyer, spokesman for the U.N. Office for the Coordination of Humanitarian Affairs, declined to identify all who were involved except to say that various actors had put great effort into getting trapped people off Mount Sinjar.
The United States and Britain have air-dropped humanitarian aid in recent days to thousands of Yazidis trapped in searing heat on the mountain near the Syrian border, and Washington has bombed the Islamic State Sunni insurgents in its first military action in Iraq since withdrawing troops in 2011.
The Yazidis fled to the mountain last week to escape the Islamist militants, who deem Yazidis "devil worshippers." The Yazidis follow an ancient faith derived from Zoroastrianism.
"In the last 72 hours some thousands of people have been able to get off the mountain, escaping with the assistance of the Kurdish security forces and others," Dwyer told reporters by phone from Arbil, capital of Iraqi Kurdistan.
Dwyer said most who had escaped the mountain had been trapped on the north side. They then had a seven-hour walk, at times traveling in vehicles, through Syria before crossing back into the safety of Iraq's Kurdistan region.
The U.N. refugee agency said 31,000 Iraqis, most from Mount Sinjar, had crossed from Syria into Kurdistan in recent days.
"People are trapped in multiple locations on the mountain, and on the south side is where they are mostly exposed to the armed groups," Dwyer said.
Dwyer said air drops of aid were critical to keeping those still on the mountain alive until an escape route could be secured. The U.N. mission in Iraq has said it is preparing a humanitarian corridor to allow Yazidis to flee.
"One single corridor is not necessarily the way that it's happening at this point and I stress that when people get off the mountain they still have to get through some very difficult territory before they get into a safe zone," Dwyer said.
The Islamic State, which has declared a caliphate in parts of Iraq and Syria to rule over all Muslims, poses the biggest challenge to the stability of Iraq since the fall of Saddam Hussein in 2003. (Reporting by Michelle Nichols; Editing by Howard Goller)