Last Updated Aug 17, 2014 6:40 PM EDT
ERBIL, Iraq - An Iraqi security official says Kurdish forces have taken over parts of the country's largest dam, which was captured by the Islamic State of Iraq and Syria extremist group earlier this month.
Kurdish officials say that peshmerga forces backed by Iraqi and U.S. warplanes started the operation to retake Mosul Dam early Sunday.
Officials told CBS News correspondent Charlie D'Agata that the peshmerga have not only started closing in on the dam already, but it appears ISIS fighters have begun withdrawing from some surrounding villages.
Their withdrawal has not been simple, however. Officials tell D'Agata ISIS fighters are believed to have booby-trapped the road leading to the dam with explosives, slowing the peshmerga fighters' advance.
A commander with the Kurdish forces at the dam, which was seized on Aug. 7, said they now control the eastern part of the dam and that fighting is still underway.
The U.S. launched airstrikes against ISIS more than a week ago in a bid to halt its advance across the north. The extremists control vast swaths of Iraq and neighboring Syria.
ISIS, also known as the Islamic State of Iraq and the Levant, or ISIL, took the dam just more than a week ago, CBS News' D'Agata reported. It is Iraq's biggest. If it were destroyed or opened, it could cause catastrophic flooding.
Peshmerga fighters have gone on the attack in recent days trying to retake territory in northern Iraq that was lost to ISIS. But the soldiers told CBS News they're simply outgunned and they don't have heavy weapons and equipment to match the ones that ISIS stole from the Iraqi military.
The soldiers are asking for more help from the U.S. and European allies, and they're heavily reliant on U.S. airpower in terms of surveillance and airstrikes, D'Agata reported.
Meanwhile, Kurdish officials said that as many as 350 ethnic Yazidi men were executed. They were told to convert to Islam or die. Additionally, as many as 1,000 Yazidi women and children may have been abducted.
A Yazidi lawmaker and a Kurdish security official said fighters from ISIS massacred scores of Yazidi men Friday afternoon after seizing the village of Kocho. Both said they based their information on the accounts of survivors and warned that the minority group remains in danger despite U.S. aid drops and airstrikes launched to protect them.
ISIS fighters besieged the village for several days and gave its Yazidi residents a deadline to convert to Islam, Yazidi lawmaker Mahma Khalil said Saturday.
"When the residents refused to do this, the massacre took place," he said.
Halgurd Hekmat, a spokesman for Kurdish security forces, said the militants took the women and children of Kocho to the nearby city of Tal Afar, which is controlled by ISIS.
Their accounts could not immediately be confirmed. Areas held by the extremist group are not accessible to reporters.