WASHINGTON (AFP) - The United States-led coalition operating in Syria will investigate allegations of civilian casualties near the Syrian town of Raqa, a Pentagon spokesman said on Wednesday (March 22).

"Since we have conducted several strikes near Raqa we will provide this information to our civilian casualty team for further investigation," the spokesman said, following reports that a coalition strike killed 33 civilians in the northern Syrian province of the same name.

The civilians were killed in the reported air strike early Tuesday, according to the Syrian Observatory for Human Rights.

The monitor said on Wednesday that the strike hit a school being used as a temporary shelter for displaced families, about 30km west of ISIS-held Raqa city.

"We can now confirm that 33 people were killed, and they were displaced civilians from Raqa, Aleppo and Homs," said Observatory head Rami Abdel Rahman.

"They're still pulling bodies out of the rubble until now. Only two people were pulled out alive," Abdel Rahman told AFP.

The air strike came ahead of a Wednesday meeting of top officials in Washington focused on defeating the ISIS group.

Years of diplomatic efforts have failed to end Syria's raging six-year conflict, which began with protests against President Bashar al-Assad.