* Some left family members to strike out for safety
* Shelled by Islamic State fighters
* U.S., U.N. seek secure corridor
By Isabel Coles
DOHUK, Iraq, Aug 11 (Reuters) - Exhausted and terrorized, many of the Yazidis of northern Iraq who straggled into this Kurdish town after escaping the Islamic State deathtrap of Mount Sinjar recalled the agony of leaving relatives exposed on the mountain.
Dakheel, 64, a shepherd who fled with family members into the rocky gullies above the sheep-grazing areas around Sinjar, left his 95-year-old mother when he set off on a grueling, risky walk to safety.
"I left my mother behind on the mountain in a cave. She said 'I want to stay here: go, save yourselves,'" Dakheel said.
He and several thousand others escaped in the last few days by climbing down the west side of the mountain, traversing the dry plain to the Syrian border and traveling north to cross back into Iraq's Kurdish region untouched by Islamic State gunmen.
The Yazidis were just one of the communities fleeing their villages from advancing Islamic State fighters who drove looted armored vehicles and fired machine guns and raised their black flag over towns across northwest Iraq in recent weeks.
For many who fled to the craggy gullies of Mount Sinjar, helped by thinly lightly armed Kurdish Peshmerga warriors and some Yazidi guards, U.S. and Iraqi military airdrops of food and drinking water in the last five days came too late.
Survivors reaching Dohuk said on Monday for the people of Sinjar the nightmare began when Islamic State forces shelled the town early last week and routed Kurdish fighters, sending thousands of people fleeing up the road to the mountain.
It was no safe refuge.
"When we went up the mountain, snipers were firing at us. The girls were throwing themselves off the top of the mountain," said Khalaf Hajji, who worked at a school. "We have lost all our faith in Iraq. They have hundreds of our women," he said.
DYING OF HUNGER
There was only the scarce food, water and medical supplies that people could carry with them, and no shade from the scorching sun.
"On the mountain ... more than 30 people died of hunger. We went back 100 years in time on that mountain," said Mural, a policeman. He recalled how one man became so desperate he killed his five sisters and himself to escape the agony.
The United States said it mounted a series of air attacks on Islamic State positions on Monday, with targets including roadblocks and vehicles, near Mount Sinjar. Earlier, planes hit artillery that had been shelling the mountain.
In Washington and at the United Nations, officials say they are working on ways to establish a safe corridor to bring all the remaining people off the mountain, but there was no sign this would be created soon.
"We are, right now, gripped by the immediacy of the crisis. And our focus right now is to provide immediate relief to those that are suffering," Lieutenant General William Manville, a senior Pentagon official said on Monday.
Asked if there would be a safe passage soon, he said: "(We are) currently assessing what we can and can't do" and "looking at the effect that we're having on ... (militant) sites that are laying siege, and we're trying to reduce that threat," he said.
Kieran Dwyer, spokesman for the U.N. Office for the Coordination of Humanitarian Affairs now in Argil, Kurdish, said he and others were working to set up safe routes for those still trapped.
Dwyer told reporters in New York by telephone: "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."
Despite the misery on the mountain, tens of thousands are still taking whatever refuge they can there, aware of the deadly threat the militants present.
Mural, the policeman, said when the militants who took over Sinjar grew frustrated that they could not remove the rings from women's fingers, they cut off fingers.
Iraq's human rights minister, Mohammed Shiva al-Sudani, said in Baghdad on Sunday that the Islamic State fighters, who view the Yazidis as "devil worshippers," killed at least 500 of them in their onslaught last week.
Some victims, including women and children, were buried alive and 300 women were kidnapped as slaves, he said. (Writing by Michael Georgy; editing by David Storey and Richard Chang)