WASHINGTON, Nov. 13 (Xinhua) -- U.S. troops will fight the Islamic State (IS) in Syria "as long as they want to fight," U.S. Defense Secretary Jim Mattis said Monday.
The U.S. forces will not "walk away" to "let ISIS pop back around," Mattis, referring to the group by another acronym, told reporters at the Pentagon, while U.S.-backed forces were retaking most of terrain formerly occupied by the group.
"The enemy hasn't declared that they're done with the area yet, so we'll keep fighting as long as they want to fight," said the U.S. defense chief.
IS has become stripped of its major strongholds in Syria and Iraq over the last few months.
The extremist militants lost their de facto capital of Raqqa last month to the U.S.-backed Syrian Democratic Forces, and this month they lost their major stronghold of Deir al-Zour city to the Russian-backed Syrian government forces.
However, one day before Mattis' remarks, the Syrian Foreign Ministry accused the U.S.-led anti-terror coalition of hindering the Syrian army's operations against IS.
The ministry said in a statement on Sunday that IS militants were waging attacks on the Syrian army positions from areas controlled by the coalition's allies on the ground, meaning the Kurdish-led Syrian Democratic Forces and other U.S.-backed forces.
The ministry's statement came as the Syrian army lost the key city of al-Bukamal to IS again after capturing it last week.