More than 100 people were killed in airstrikes that hit two markets in Yemen on Monday, according to witnesses and officials, as a Saudi Arabian-led coalition continued aerial attacks against Houthi rebels for a fourth month.

Many civilians were among the dead, according to a spokesman for the Health Ministry in Sanaa, the capital. Health officials broadcast radio and television messages urging citizens to donate blood as hospitals tended to the injured.

One airstrike occurred midday Monday at a popular livestock market in suburban Fayoush, about nine miles north of the southern port of Aden. […]