SANAA, Yemen (AP) — Yemeni officials and witnesses say heavy fighting between pro-government forces and Shiite rebels in the north and around the Red Sea port of Hodeida has killed at least 18 civilians.

They said Wednesday that forces backed by a Saudi-led coalition have been trying to seize the rebel-held district of ad-Durayhimi in Hodeida, in fighting that has killed at least 13 civilians in the past 24 hours.

They say rebel shelling has killed five people from one family in al-Sadah village, in the northern Hajjah province.

The officials spoke on condition of anonymity because they were not authorized to brief the media, while the witnesses did so for fear of reprisals.

The coalition has been at war with the Iran-allied rebels, known as Houthis, since March 2015.