The so-called Syrian Observatory for Human Rights told AFP that Saturday's airstrikes "carried out by Iraqi aircraft killed at least 20 Daesh fighters in Baghouz."
He said at the same time the Iraqi army units stationed nearby on the border with Syria fired artillery.
Last month, Iraq's government hinted at greater involvement for its armed forces in Syria as the US begins withdrawing troops from the Arab country.
Baghdad has carried out several air raids in Syrian territory with the agreement of President Bashar Assad. Its army has reinforced at the border in recent months.
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