A series of airstrikes by the Saudi-led military coalition on Tuesday struck Yemen's Defense Ministry building, which is under control of Shiite rebels who last year seized the capital, Sanaa, officials said.

The airstrikes also targeted the homes of military commanders allied with the rebels in the northwest Sanaa district of Hamdan, the officials added. A total of 121 coalition aircraft bombed eight other provinces, including sites near the Saudi border and Red Sea, killing dozens, they said.

Yemen has been targeted in Saudi-led airstrikes since March 26 as the coalition tries to halt the advance of the Iran-backed Shiite rebels, known as Houthis, and their allies.

The Houthis seized Sanaa in September and later captured much of northern Yemen before moving south in March. Their advance forced internationally recognized President Abed Rabbo Mansour Hadi to flee the country to neighboring Saudi Arabia.

Also Tuesday, fighting between tribes loyal to Hadi and forces allied to former autocratic President Ali Abdullah Saleh killed at least 15 form both sides and wounded a dozen in Marib province. Heavy fighting also continued in the streets of Taiz city, with both sides firing tanks and mortars.

Overnight, heavy airstrikes targeted rebel positions in the southern cities of Aden and Ataq, and the northern city of Saada — a rebel stronghold, the officials said, speaking on condition of anonymity because they were not authorized to talk to the media.

Meanwhile, the International Red Cross and Red Crescent Movement said the organization's volunteer worker Jameela Naji Burut was killed in an explosion on May 29 in the north-western Yemeni city of Hajjah. In a statement released Monday, the group said she specialized in vocational training and was killed while helping wounded civilians during an attack in the area. Her death brought to four the number of the group's aid workers killed in Yemen since April.