ISIS has beheaded four teenagers and young men in its Syria stronghold of Raqa for allegedly providing intelligence to the US-led coalition, AFP reports.

The Syrian Observatory for Human Rights said ISIS beheaded them after accusing them of "photographing sites and handing information to the crusader coalition causing bombing and the death of Muslims."

"ISIS Executed 4 people they Accused them for spying for Coalition," citizen journalist group Raqa is Being Slaughtered Silently (RBSS) said on Twitter.

RBSS documents abuses in areas under ISIS control in Syria.