The Pentagon said Friday it played no part in an unusual deal in which Islamic State jihadists were allowed to leave a key town in Syria -- only for some of them to be killed anyway.
The US-backed Syrian Democratic Forces had independently cut a deal with the jihadists that let a group of about 70 of them leave Tabqa, an important city by a dam near the IS stronghold of Raqa.
But as soon as they left the city, US aircraft tracked and killed several of them, officials said.
"This was an agreement for them to leave the Tabqa dam and to leave the remaining portions of the city that ISIS held," Pentagon spokesman Jeff Davis said.
"It doesn't change the fact that when we see ISIS fighters on the battlefield and have a clean shot at them, we will continue to take it."
Davis stressed the jihadists were not considered to have surrendered.
According to a US official, the SDF deal had been in the works for a couple of weeks.
The US knew about it, but "it wouldn't have been our preference," the official told AFP.
The SDF, a Kurdish-Arab alliance fighting IS in Syria, allowed the fighters to leave Tabqa in return for dismantling bombs surrounding the dam, surrendering their heavy weapons and quitting Tabqa city.
Nothing about that precluded the jihadists from being pursued, Major Adrian Rankine-Galloway said.
"This is combat. They didn't make a deal with us," he said.
Military leaders frequently say the objective is to annihilate IS, and for the most part the jihadists have fought to the death rather than surrender to security forces in neighboring Iraq or the SDF in Syria.
The US official said America always observes the laws of armed conflict and Geneva Conventions, meaning an unarmed IS fighter waving a white flag would not be targeted.
The seizure of Tabqa in the north of Syria after weeks of fighting represents one of the most important victories for the SDF.
Davis said a dam-assessment team was headed to the structure to make sure it had not been damaged by IS, although so far there had been no issues detected.
Last week the Pentagon announced President Donald Trump had approved supplying arms to the Kurdish contingent of the SDF, a controversial decision that has angered Turkey, which views the fighters as terrorists.
"We are very mindful of the Turkish concerns on this," Davis said.
"We are going to assure that every step of the way that we are receiving assurances from the SDF that they are using (the weapons) only to fight ISIS. We will be monitoring it in real time."
© 2017 AFP