Islamic State fighters pressed their assault on two key towns in Syria and Iraq on Thursday as defenders on both fronts prepared for possible street-by-street battles and appealed for intensified U.S.-led airstrikes, reports and witnesses said.

The two showdowns — in the Euphrates River town of Hit in Iraq and the strategic Syrian crossroads of Kobane near the Turkish border — suggest that the Islamic State retains enough firepower and command structure to make continued gains despite weeks of airstrikes by Western and Arab nations.

The clashes also have exposed weaknesses among the ground forces trying to blunt the extremist group’s push. Such worries have been raised in Turkey, whose parliament Thursday gave the green light for possible military intervention in the two neighboring countries.

Turkey, which has a vast and well-equipped military, had previously sent reinforcements to the border but had remained on the sidelines of the international coalition fighting the Islamic State. The parliament’s nod to an active Turkish role in the fight could mark a significant shift in tactics.

In Syria’s northern Kurdish region, Islamic State militants appeared to be moving closer to the border town of Kobane, which has been under near-constant attack for more than two weeks. The battles have sent more than 160,000 people fleeing to Turkey or seeking safety in enclaves outside the group’s reach.

Allied airstrikes Oct. 1-2

A senior Syrian Kurdish commander, Ismet Sheik Hasan, said forces defending Kobane were digging in for possible urban combat in the event that Islamic State fighters breach the last lines ringing the town, also known in Arabic as Ayn al-Arab.

The U.S. military said the United States and partner nations launched four airstrikes against the Islamic State in Syria on Wednesday and Thursday.

In Iraq, the loss of Hit, a town on a major pipeline route and about 115 miles northwest of Baghdad, would further consolidate the Islamic State’s hold on Sunni-dominated areas stretching from near the capital to Mosul, the largest city in the north. The region was once a key battleground between insurgents and Sunni tribes recruited by the United States to fight on its side after the 2003 invasion.

Now, Washington and its Iraqi partners are trying to forge a similar alliance to help battle the Sunni-led Islamic State, an al-Qaeda offshoot.

Just before dawn Thursday, militants using car bombs targeted the Hit police headquarters and a checkpoint, local officials said.

The officials said coalition warplanes attacked the militants, forcing them to retreat. The U.S. military said the international coalition conducted seven airstrikes in Iraq on Wednesday and Thursday.

A member of the local council in Hit, Mohannad Mizbar, said Thursday afternoon local time that Islamic State fighters continued to battle Iraqi troops on the outskirts of the city.

Amateur video purports to show Islamic State militants clashing with Kurdish fighters in Kobane, near the Syrian-Turkish border, as refugees flee for their lives. (Reuters)

But a resident of Hit contacted by telephone said later that Islamic State fighters had raised their group’s flag over the mayor’s office in the city center and that street-to-street battles were raging between the insurgents and Iraqi security forces by nightfall.

Also Thursday, Islamic State militants assaulted a large army base in the western Iraqi city of Ramadi, detonating car bombs and firing mortar rounds. Security forces eventually repelled the attack, officials said.

Ramadi is one of the last major areas of Anbar province, where Hit is also located, that are still under government control. Jihadists have maintained a strong presence in Anbar since January, and the government has struggled to roll back their gains.

“The area is very strategic,” said Sheik Ahmed Abu Risha, a prominent pro-government tribal leader in the area. “They want to attack it to make people feel unsafe,” he said of the militants.

In Geneva, a U.N. report released Thursday cited widespread atrocities and abuses at the hands of the Islamic State, including mass executions and beheadings, the sale of captive women and girls as sex slaves, and targeted attacks against religious minorities, including Christians and Yazidis, members of an ancient sect.

The report by the U.N. Office of the High Commissioner for Human Rights and the U.N. Assistance Mission for Iraq could help lay the groundwork for eventual charges of war crimes and crimes against humanity.

The report added that more than 24,000 civilians were killed or injured in violence in Iraq during the first eight months of this year — the highest such toll since the height of sectarian battles and the insurgency against U.S. forces more than seven years ago.

Murphy reported from Washington. Mustafa Salim contributed to this report.