Iraqi forces on the move during a battle with Islamic State's militants outside Mosul on Feb. 24, 2017. (Zohra Bensemra/Reuters)

Iraqi jets struck Islamic State targets inside neighboring Syria for the first time Friday, Iraq’s prime minister said while vowing to chase down militants “everywhere” as Iraqi troops opened new fronts in their battle for the city of Mosul. 

The airstrikes in Bukamal, in Syria, were coordinated with Damascus and carried out through a joint intelligence-sharing and command center in Baghdad involving Syria, Iran, Iraq and Russia, according to Brig. Gen. Tahseen Ibrahim, a spokesman for Iraq’s Defense Ministry. He said he had no information on whether the strikes also were coordinated with the U.S.-led coalition, which is conducting airstrikes against Islamic State targets in Syria and Iraq and providing close air support to Iraqi forces fighting the group

The strikes came as Iraqi forces are reaching the final stages of their operation to oust the group from the northern city of Mosul, its largest remaining stronghold in Iraq. 

Backed by U.S.-led coalition jets, Iraqi ground forces made their first incursion into western Mosul on Friday after securing the airport on the city’s southwestern edge. Commanders said progress had been quicker than expected. 

The eastern side of Mosul was recaptured earlier in the grueling offensive, which was launched in October. 

But even as it loses ground, the Islamic State has continued to bomb civilian targets elsewhere in Iraq and Syria, where blasts near the northern town of al-Bab killed at least 50 people Friday. 

“We are determined to follow the terrorism that is trying to kill our sons and our citizens everywhere,” said Iraqi Prime Minister Haider al-Abadi. Iraqi officials said they had information that recent attacks in Baghdad had been organized from inside ­Syria. 

The cars used in those blasts, including one that targeted a market in Baghdad’s southwestern Bayaa neighborhood this month that killed at least 45 people, had been rigged with explosives in Bukamal and in Husaybah, on the Iraqi side of the border, Iraqi officials said. Husaybah was also the target of airstrikes Friday.

Iraq decided to carry out the strikes rather than rely on the U.S.-led coalition because it was acting on the basis of Iraqi intelligence and “it’s up to us to take revenge,” said Lt. Gen. Anwar Hana, commander of Iraq’s air force. The strikes were successful, he said.

Iraq’s Joint Operations Command released video of the missiles hitting buildings.

The Islamic State has lost more than half of the territory it once controlled in Iraq, but headway against the group has been slower in Syria. 

However, Turkey-backed Free Syrian Army rebels recaptured al-Bab on Thursday, pushing the Islamic State from its final foothold along Syria’s northern border with Turkey.

That offensive, which began in early December, has reduced much of al-Bab to a ghost town, its prewar population of about 100,000 having dwindled to the low thousands.

Suspected Islamic State car bombs killed at least 50 people in the village of Sousyan, about six miles northwest of al-Bab, on Friday, witnesses and the opposition-activist-run Aleppo Media Center said. 

The attacks hinted at the scope of the challenges facing the Turkey-backed forces as they seek to restore security to areas they have been retaken from the Islamic State.

In Iraq, commanders said that they were making rapid progress against the militants in western Mosul, after an offensive for the second half of the city was launched a week ago.

Before the offensive began, military officials said they were unsure what levels of fighters and resources the militants had kept in reserve to defend the western side of the city, which is more densely populated than the eastern side.

“We are advancing faster than expected,” said Lt. Gen. Sami al-Aradhi, from Iraq’s counterterrorism forces. He said that “tens” of Islamic State militants surrendered Friday and that Iraqi forces have retaken the Ghizlani military camp on the city’s outskirts and stormed the Mamon neighborhood.

The Islamic State used car bombs, snipers and weaponized drones to slow the advance.

Morris and Loveluck reported from Beirut. Zakaria Zakaria in Istanbul, Suzan Haidamous in Beirut and Brian Murphy in Washington contributed to this report.