More than 46,000 people have been driven from their homes in Yemen in the wake of the latest escalation in fighting in the war-torn country, according to UN data.
"Families are being forced to flee for the second or third time in this conflict, with almost nothing left," said Amy Pope, head of the International Organization for Migration (IOM), according to a statement.
It said many people had reportedly left the port city of Mokha overnight with their belongings, after the Iran-allied Houthi rebels captured the strategically important city on Thursday.
Entire villages were said to have been abandoned in some areas of the war-torn country. The IOM urged the parties to the conflict to guarantee humanitarian access and ensure the safety of volunteers.
On Friday, the militant Islamist Houthis captured a strategically located island in the Bab al-Mandab strait. The Houthis now control Yemen's entire Red Sea coast.