Buses carrying hundreds of ISIL militants and their families arrived in eastern Syria on Tuesday following a negotiated evacuation from the Lebanon-Syria border, where the US-backed Lebanese army deployed for the first time in years.
The evacuation agreement, the first such publicised deal reached with the extremist group, angered many Iraqis, who accused Syria and Hizbollah of dumping the militants on the Iraqi border rather than eradicating them.
Some 600 militants were allowed to leave as part of a deal, negotiated by Hizbollah, in exchange for identifying the location of the remains of Lebanese soldiers captured by ISIL in 2014 and later killed. The deal also provoked controversy in Lebanon, as some have voiced opposition to negotiations with the militants.
"Any deals or understandings between the warring parties inside Syria or in the region must take into consideration the security of Iraq and not to lead to anything that poses any threat to our national security," the Iraqi government spokesman, Saad Al Hadithi, told The Associated Press on Tuesday.
Mr Al Hadithi said the Iraqi government "will firmly face any threat to Iraqi territories."
Meanwhile in northern Syria, US-led coalition forces returned fire after being repeatedly shot at near Manbij where they are patrolling near areas held by Turkish-backed rebels.
"Our forces did receive fire and return fire and then moved to a secure location," coalition spokesman Colonel Ryan Dillon told Reuters on Tuesday.
The incident reflects the complexity of the battlefield in northern Syria, where the Russia-backed Syrian army, Kurdish forces aided by the US-led coalition and Syrian rebels supported by Washington's ally Turkey are all operating.