As Iraqi ground troops pushed into western Mosul on Friday, the country's air force struck Islamic State group targets inside Syria for the first time in response to recent bombings in Baghdad claimed by the militants.
Meanwhile, at least 60 people were killed in IS attacks near a key northern Syrian town captured only a day earlier from the extremists by Turkish forces and their Syrian opposition allies.
Iraqi Prime Minister Haider al-Abadi announced the Iraqi airstrikes in Syria in a statement, saying the border towns of Boukamal and Husseibah were targeted in response to recent bombings in Baghdad linked to Islamic State group operations there.
Iraqi forces closely supported by the U.S.-led international coalition pushed into the first neighborhood of western Mosul and took full control of the city's international airport and a sprawling military base on the southwestern edge of the city, according to Iraqi officials.
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The territorial gains were the most significant yet in the battle, now in its sixth day, to rout IS militants from the western half of Iraq's second-largest city.
As Iraqi warplanes struck IS targets across the border, militants in northern Syria staged a suicide car bomb attack outside a security office operated by the Syrian opposition in a village five miles (eight kilometers) north of al-Bab, killing at least 60 people. The town had been controlled by IS since late 2013, but the militants finally retreated Thursday after more than two months of intense fighting.
Most of those killed in the village of Sousian were civilians awaiting permits and an escort to return to al-Bab, a Syrian military commander in the city told The Associated Press. At least six fighters were among those killed in the attack, according to Turkey's prime minister, who spoke in Ankara.
Hours after the first explosion in Sousian, another car bomb attack was reported in the village, killing at least eight people, according to activist groups. There were no further details on the attack, and the Aleppo Media Center later took down the report.
An additional explosion was reported south of al-Bab, where two Turkish soldiers were killed when an explosive device went off as they were removing land mines, Turkey's military said. The Britain-based Syrian Observatory for Human Rights corroborated the report, saying the explosives detonated near Tadif, an IS-controlled town south of al-Bab. Turkish Prime Minister Binali Yildirim, however, called the explosion a "suicide attack." It was not immediately possible to reconcile the accounts.
In Mosul, meanwhile, Iraqi forces pushed into the Mamun neighborhood and engaged in intense clashes with IS militants, according to an Iraqi special forces officer on the ground, who spoke on condition of anonymity in line with regulations.
Federal police Maj. Gen. Haider al-Maturi said his forces pushed through concrete roadblocks and earthen berms set up by the Islamic State group, and succeeded in capturing around 30 percent of the Aviation District, the first district entering Mosul's western perimeter from the south.
"There were fierce clashes. We faced car bombs, suicide attackers and mortar shelling," al-Maturi said. "The battle ahead will be difficult and complicated because of the civilians around. It'll be street fights."
Al-Maturi said six Iraqi troops were wounded, including two officers. However, an AP team near the front line saw at least four wounded special forces' members and the bodies of three soldiers, suggesting more intense fighting than the previous day. A Canadian medic volunteering at a front-line clinic said he had treated at least 10 wounded federal policemen. Iraq's military does not release official casualty figures.
Earlier on Friday, the spokesman of the Joint Military Operation Command, Brig. Gen. Yahya Rasool, said Iraqi forces had also retaken the military base adjacent to the airport.
The advances came a day after special forces joined the fight for western Mosul.
Both the Ghazlani military base and the airport will be key to the next steps in the daunting battle and will serve as a base of operations as Iraqi forces launch subsequent pushes into western Mosul, which is divided by the Tigris River into two halves.
Iraqi authorities declared the city's eastern half "fully liberated" from the Sunni militants in January, three months after launching the operation to take back Mosul.
The United Nations estimates about 750,000 civilians are trapped in western Mosul. The initial numbers of displaced have been low, but Iraqi forces have yet to punch into the sector's dense urban neighborhoods, an operation that is expected to be the most difficult yet. The western half of the city is denser, with older neighborhoods and narrower streets that will likely complicate the already difficult urban combat ahead.