The health ministry of the Houthi rebel-controlled government in Yemen increased the death toll of an airstrike that hit a bus to 51, adding that at least 79 were injured.

On Thursday, an airstrike, which the Saudi-led coalition is suspected of being behind, hit a bus carrying children on their way to an educational summer camp organized by the Ministry for Islamic Affairs near the northwestern city of Saada, killing at least 40 minors.

Two other buses were also targeted.

Missing and unidentified victims are expected to further increase the death toll, said a Houthi health ministry spokesman, Yusef al-Hadari.

Hospital sources confirmed that vendors and customers at the Dahian market were among the victims.

Earlier on Friday, the European Union denounced deadly attacks intended to strike military targets in Yemen and advocated for a political solution to the conflict.

The province of Saada, near the border with neighboring Saudi Arabia, is the main bastion of the Houthis, a Zaidi Shia-led movement backed by Iran that launched an insurgency against the Sunni-controlled government in the capital Sana'a in 2014.

A military coalition led by Saudi Arabia has been conducting devastating airstrikes since 2015 against Houthi positions, causing thousands of civilian deaths in the process, according to war monitors, in an attempt to restore the internationally-recognized government of President Abdrabbuh Mansur Hadi, which is currently based in the southern port city of Aden.