At least 57 people are killed as pro - Saudi militants battle Houthi fighters and Yemeni army forces in a push to capture Yemen ' s third biggest city of Ta ' izz. Military sources said 37 members of the Yemeni army and their allied Houthi fighters and six civilians were killed in Friday clashes which involved airstrikes by Saudi warplanes. Fourteen militants loyal to former president Abd Rabbuh Mansur Hadi were also killed. Medical officials said most of the casualties were caused by Saudi aerial assaults. Saudi Arabia has been pummeling Yemen from the air, sea and ground for a year now in a bid to restore Hadi to power. Ta’izz governor Ali al-Maamari said pro-Hadi forces captured areas in the western and southern suburbs of Ta'izz, including the al-Misrakh district. Local witnesses, meanwhile, said al-Qaeda-linked militants had kidnapped a number of Houthi fighters in Ta’izz. Ta’izz, widely known as Yemen’s cultural center, has been under the control of Houthi fighters and allied army forces for over a year now. The city is located between the capital Sana'a and the southern port city of Aden, which pro-Hadi militants overran in July. Aden has been wracked by violence and chaos since the fall and attacks by Takfiri groups have become a regular occurrence. In November, pro-Hadi forces announced a major offensive to try to take Ta'izz. On Saturday, Saudi fighter jets bombarded residential areas in Khwlan District of Yemen’s western province of Sana’a, leaving an unknown number of people, mostly women, dead or injured. Saudi jets also pounded Majzar District of central Ma’rib Province, Yemen’s al-Masirah news channel reported. In retaliation, the Yemeni army forces fired a ballistic missile at a center of gathering belonging to Saudi mercenaries at the al-Anad Air Base in Yemen’s southwestern Lahij Province. According to pro-Hadi media, five Katyusha rockets hit an area west of the strategic air base, but the strikes caused no damage. Meanwhile, another Saudi base between Ma’rib and the province of Bayda came under Yemeni rocket attacks. At least 8,400 people have been killed and over 16,000 others sustained injuries since the onset of the Saudi war. The military campaign has also taken a heavy toll on the impoverished state’s facilities and infrastructure, destroying many hospitals, schools, and factories. Yemenis have been carrying out retaliatory attacks on the Saudi forces deployed in the country as well as targets inside Saudi Arabia.