The attack on Tuesday afternoon hit a group of civilians in the Mawza district of the southwestern province of Taez.

Residents said the attack was carried out by a warplane from the Saudi-led coalition fighting Shiite rebels in support of Yemen's internationally recognised government.

At least seven women and four children were among those killed.

The UNHCR said it was "deeply shocked and saddened at reports of the deaths and injuries of a number of internally displaced persons in an aerial attack" on the area.

The statement said the civilians had fled fighting in the nearby Mokha district, on the Red Sea coast.

Coalition-backed forces loyal to President Abedrabbo Mansour Hadi recaptured the port of Mokha in February as part of a major ongoing offensive to drive rebels from Yemen's lengthy coastline.