The Syrian army has killed two Islamic State commanders in an air strike in central Syria along with at least 24 other members of the ultra-hardline group, a monitoring group said on Saturday.

Syrian state media reported the death of one of the Islamic State commanders killed in the air strike. It identified him as one of the group's self-declared provincial governors, Deeb Hedijan al-Otaibi.

Islamic State supporters circulated a statement on Twitter announcing the "martyrdom" of the same man, together with photos showing him dead and alive. Otaibi was also identified as Abi Ammar al-Jazrawi, likely to be his nom de guerre.

The Syrian Observatory for Human Rights, the monitoring group, said a total of 26 Islamic State militants were killed in the air strike near the town of Hamadi Omar, some 50 km (30 miles) southeast of the city of Hama.

Syrian state media said a convoy of dozens of military vehicles had also been destroyed in the air strike.

Rami Abdulrahman, who runs the Syrian Observatory for Human Rights, said it was not clear if the air strike had been launched on Friday or Saturday.

A U.S.-led alliance that is bombing Islamic State in both Syria and Iraq has rejected the idea of partnering with President Bashar al-Assad in the fight against the group, describing him as part of the problem.