At least 70 Islamic State (IS) Sunni extremist militants were killed and 300 more were wounded in airstrikes on Syrian territory launched by warplanes of the US-led international coalition Tuesday, the Syrian Observatory for Human Rights (SOHR) said.

SOHR indicated that the militants were killed in bomb attacks that targeted their positions in the northern Syrian provinces of Raqaa, Deir al-Zur and al-Hasakah.

The London-based NGO expected the number of victims to increase as more than 100 jihadis were evacuated to Iraq where they are said to be in serious condition.

Tuesday’s raids mark the first time US warplanes have attacked targets in Syria. Bahrain, Jordan, Saudi Arabia, Qatar and the United Arab Emirates also took part in or supported the airstrikes against the IS targets.

According to SOHR, the alliance launched more than 50 attacks in a matter of hours on IS bases and installations, many of which had been evacuated last week.

The government of Syrian President Bashar al-Assad announced Tuesday that it supports any international effort against the jihadi groups as long as it respects national sovereignty and is consistent with international decisions.