Yemeni officials say overnight fighting between the country's Shiite rebels and pro-government in the southwestern Taiz province has killed 31 people, including eight civilians.

The officials also said Saturday that the rebels, known as Houthis, are blocking the flow of humanitarian aid to the provincial capital, also called Taiz, which is in government hands.

The rebels have been besieging Taiz for months and have prevented the delivery of essential aid to the war-ravaged city for months.

Yemen's conflict pits the country's internationally recognized government and the U.S.-backed Saudi-led coalition against the Houthis, who are allied with Yemen's longtime former president.

The officials, who back neither side in the conflict, spoke on condition of anonymity because they are not authorized to talk to reporters.