The UN children's fund has condemned a blast near two schools in Yemen's rebel-held capital Sana'a that it said killed 14 children and critically injured 16.
"It is hard to imagine the sheer horror that those children experienced," UNICEF Regional Director for the Middle East and North Africa Geert Cappelaere said of Sunday's blast in a statement.
"And the sheer horror and guilt parents may feel for having done what every parent aspires to: sending their children to school."
On Sunday, the Iran-backed Houthi rebels said at least 11 civilians, mostly students, were killed by Saudi-led coalition bombing of houses and a school in a residential area in Sana'a.
Yemen has been embroiled in a devastating conflict between the Saudi-backed government and the Houthis since late 2014.
The feud has intensified since March 2015, when the Houthis advanced on the government's temporary capital of Aden, prompting Saudi Arabia and its Sunni allies to start an air campaign against the Shiite group.