Yemeni officials and witnesses say heavy fighting between pro-government forces and Shiite rebels in recent days has killed more than 150 people.
Government forces have been trying to seize rebel-held areas along the western coast, while an allied Saudi-led coalition has been targeting the rebels with airstrikes in the northwestern Saada province.
Security officials say a Saudi-led airstrike in the capital, Sanaa, killed four civilians on Saturday and wounded 10.
The officials spoke Sunday 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 battling the Iran-allied rebels, known as Houthis, since March 2015 in a war that has killed more than 10,000 people. The Houthis control much of northern Yemen, including Sanaa.