Operations at a Red Sea port in Yemen used for aid imports have fallen to about a quarter of its capacity, a UN official said on Tuesday, adding it was not certain that a Gaza ceasefire would end attacks between the Iran-backed Houthis and Israel.

Four of the port's five tugboats needed to escort the large ships bringing imports had sunk, while the fifth was damaged, a UN official has said.

Yemen's Houthis will limit their attacks on commercial vessels to Israel-linked ships after the Gaza ceasefire came into effect, the Yemen-based Humanitarian Operations Coordination Center (HOCC), said.