Kurdish forces attacked Islamic State (IS) fighters Wednesday just 25 miles southwest of the Kurdish regional capital of Irbil in northern Iraq, a senior Kurdish official told Reuters.
Also Wednesday, local state media indicated that a suspected drone strike by the Iraqi government killed at least 30 people in the northern city of Mosul. The strike was reportedly aimed at a headquarters being used by IS, and killed at least 15 of its fighters. The report could not be independently confirmed.
Both the Kurdish offensive and apparent drone attack came after IS militants inflicted a defeat on the Kurds on Sunday with a rapid advance through three towns, prompting Iraq's prime minister to order his air force for the first time to back the Kurdish forces.
"We have changed our tactics from being defensive to being offensive. Now we are clashing with the Islamic State in Makhmur," said Jabbar Yawar, secretary-general of the ministry of the Kurdish peshmerga fighters.
The location of the clashes puts the IS militants closer than they have ever been to the Kurdish semi-autonomous region since they swept through northern Iraq almost unopposed in June.
Shortly after that lightning advance, thousands of U.S.-trained Iraqi soldiers fled. Kurdish fighters, who often boast of their battles with longtime Iraq leader Saddam Hussein's forces, stepped in as did Iranian-trained Shia militias.
Yawar said the Kurds had re-established military cooperation with Baghdad. Ties had been strained between the Kurdish leadership and the Shia-led government of Prime Minister Nouri al-Maliki over oil, budgets and land.
But the dramatic weekend offensive by the Sunni militants — who seized more towns, a fifth oilfield and Iraq's biggest dam — prompted them to bury their differences.
The capture of one of the towns, Sinjar, home to many of Iraq's Yazidi minority sect, is leading to fears of a major humanitarian crisis.
Yazidis, who are followers of an ancient religion derived from Zoroastrianism, are at high risk of being executed because they are viewed by the Islamic State militants as infidels.
Yawar said 50,000 Yazidis now hiding on a mountain risked starving to death if they were not rescued within 24 hours.
"Urgent international action is needed to save them. Many of them, mainly the elderly, children and pregnant women, have [already] died," he said.
"We can't stop the Islamic State from attacking the people on the mountain because there is one paved road leading up to the mountain and it can be used by them. They are trying to get to that road."
A Yazidi lawmaker broke down in tears during a parliamentary session on Tuesday as she urged the government and the international community to save her community from being massacred or starved into extinction.
"Over the past 48 hours, 30,000 families have been besieged in the Sinjar mountains, with no water and no food," said Vian Dakhil.
"We are being slaughtered; our entire religion is being wiped off the face of the earth. I am begging you, in the name of humanity."
On Tuesday, the U.N. Security Council condemned the latest IS attack and said it "may constitute a crime against humanity."
IS, which has declared a "caliphate" in swathes of Iraq and Syria that it controls and threatens to march on Baghdad, also hold parts of western Iraq along with other tribal allies.
Efforts to neutralize IS have been undermined by political deadlock and sectarian tensions fueling levels of violence not seen since the height of a civil war in 2006-2007.
Critics say Maliki is an authoritarian leader whose sectarian agenda has sidelined Sunnis and driven them to find common cause with the Islamic State, even though they reject the group's radical view of Islam.
Maliki, who has been serving in a caretaker capacity since an inconclusive election in April, has rejected calls by Kurds, Sunnis, some fellow Shias and even regional powerbroker Iran to step aside and make room for a less polarizing figure.
He remained defiant on Wednesday in his weekly televised address to the nation, warning any unconstitutional attempt to form a new government would open "the gates of hell" in Iraq.
Al Jazeera and wire services