Ammon News - AMMONNEWS - The coalition fighting ISIS in Syria may have accidentally hit allied rebels during an air strike at the end of last month, a US military spokesman said Saturday.

Coalition forces carried out three air strikes against tactical ISIS units and vehicles near Ma'ra on May 28, Centcom spokesman Colonel Patrick Ryder said in a statement.

"The coalition was subsequently informed that one of the air strikes may have hit counter-ISIL forces and their vehicle, instead of ISIL forces. Initial reports were that four counter-ISIL personnel may have been killed in the strike," he said, using an alternative acronym for the militant group.

He added that an investigation was under way.

"We will continue our support of counter-ISIL forces and will apply any lessons learned derived from the investigation to improve our operation in the future," Ryder said, confirming a Wall Street Journal report.

According to Centcom, the coalition had conducted three bombings that day in that area of the province of Aleppo, along the Turkish border, where heavy fighting took between rebels and militants has raged in recent weeks.

The spot hit is located as the city of Manbij further east, in the last stretch of territory along the border with Turkey still under jihadist control.

According to the Journal, the rebels hit by the bombing belonged to the Mutasim brigade, which claims to have lost 10 fighters in the strike.

The newspaper said the brigade is one of the groups that received weapons and equipment from the Pentagon as part of the US training program for Syrian rebels.

The $500 million program launched in early 2015 was suspended a few months later when the rebels failed to progress. It was relaunched this year in a simpler form.

*AFP