Activists say airstrikes by a U.S.-led coalition hit a Syrian oil refinery held by the Islamic State group.

Activists say the strikes late Sunday night targeted a refinery near the Turkish-Syrian border outside the town of Tel Abyad.

The Syrian activist group Raqqa is Being Slaughtered Silently posted a video purporting to depict the strikes, showing an enormous fireball. The video could not be immediately verified, though it corresponded with Associated Press reporting about the attack.

The Britain-based Syrian Observatory for Human Rights also reported the strikes, estimating they killed about 30 people. The other group offered no casualty figure.

The Islamic State group, which controls about a third of Syria and Iraq, sells black-market oil to fund its conquests. The U.S.-led coalition did not immediately report the strike.