Kurds say they’ve retaken territory near Sinjar Mountain in northern Iraq

Story highlights

NEW: Coalition aircraft conduct 48 airstrikes near Sinjar on Tuesday night

Kurdish forces say they fought back ISIS near Sinjar Mountain with help from airstrikes

U.S. says 1,300 airstrikes so far have killed high level officials and are slowing down ISIS

Pentagon general uses Arabic term for ISIS at news conference and calls it "Daesh"

CNN  — 

Kurdish Peshmerga forces say they’ve recaptured territory near Sinjar Mountain in northern Iraq, where dramatic airdrops were made last summer to the Yazidis, one of Iraq’s smallest minorities.

The Kurdish military says it has “cleansed” the area of ISIS fighters with the help of coalition airstrikes.

The operation represents the single biggest and most successful military offensive against ISIS, said the Kurdistan Region Security Council in a news release.

Last summer, the siege of Sinjar forced the Yazidis, one of Iraq’s smallest minorities, to flee the ISIS advance.

They found refuge in the surrounding mountains but were trapped without food, water or medical care in the heat before coalition forces airdropped supplies and rescued some of them.

Thousands of Yazidis fled on foot to Syria. Only a few hundred are left on Sinjar Mountain.

The plight of the Yazidis, coupled with the ISIS assault against Iraq’s semiautonomous Kurdish region, prompted the United States to begin targeted airstrikes in Iraq last August.

More airstrikes against ISIS

Coalition aircraft conducted 48 airstrikes near Sinjar on Tuesday night, the heaviest concentrations of airstrikes to date, according to two US defense officials.

The U.S. military says it has conducted 1,300 airstrikes to slow down ISIS.

In November, airstrikes killed two top-level and one mid-level ISIS leader, including Abu Bakr al-Baghdadi’s deputy and the emir of Mosul, a senior U.S. military official told CNN.

The most recent airstrikes were aimed at supporting Peshmerga fighters efforts to open a land corridor from Sinjar north to Dahuk in northern Iraq, officials said.

“We have opened a corridor from south of Zummar to the Mountain Sinjar,” said Masrour Barzani, chancellor of the Kurdistan Region Security Council, on Thursday.

The corridor enabled the Peshmerga to gain direct access to displaced people trapped on Mount Sinjar and to provide humanitarian support, he said.

ISIS fighters fled toward the Syrian border and ISIS strongholds such as Mosul and Tal ‘Afar, the Kurdistan Region Security Council news release said.

“ISIS is always making damage, killed the people, steal the stuff, kidnapping people, taking money from people. That’s what ISIS is doing, and that’s not Islam,” said Peshmerga fighter Khalid Suleymen Kolaoh, who was on the front line.

“We’re not seeing the broad offensive movement we saw in May and June,” Gen. James Terry, commander of Operation Inherent Resolve, told reporters at the Pentagon on Thursday.

He said the military is seeing signs that ISIS is having a hard time communicating with its fighters and resupplying them. There’s also social media traffic out of Mosul that shows an “inability of their self-declared caliphate to govern population centers,” Terry said.

An array of names for the group

During the Pentagon briefing, Terry referred to ISIS as “Daesh” for the first time. It’s the Arabic term for the terror group.

“Our partners – at least the ones that I work with, ask us to use that because they feel that if you use ‘ISIL,’ you will legitimize a self-declared caliphate, and they feel pretty strongly that we should not be doing that,” Terry said.

ISIS, ISIL or the Islamic State?

Several names have been associated with the same group this year. CNN and some other news organizations have primarily maintained the use of ISIS (for Islamic State in Iraq and Syria). The U.S. government has been using ISIL (for Islamic State in Iraq and the Levant). Earlier this year, the group declared it was calling itself simply the “Islamic State.”

Mass grave found

A mass grave with 230 bodies was discovered in Syria’s al-Keshkeyyi Desert near Deir Ezzor across the border from Iraq, according to the Syrian Observatory for Human Rights.

They were members of the al-Shaitaat people and were killed by ISIS militants, the observatory said.

ISIS had fought for control of Deir Ezzor five months ago and many fled to the surrounding countryside, said Omar Abu Leila, a spokesman for the Free Syrian Army’s Eastern Front who is from Deir Ezzor.

He said ISIS told people they could return to their homes if they put down their weapons and followed the group’s orders.

Those who came back without weapons, and no ability to fight, thought that maybe their family members were arrested, but they found a mass grave instead. “It is obviously a warning to the returning residents,” Omar said.

The bodies were decomposing, and one father told Omar, “I can’t even tell which is my son.”

Everything to know about the rise of ISIS

CNN’s Samira Said, Jim Sciutto and Chloe Sommers contributed to this story