According to witnesses and security sources, two hotels were hit by the air raids, and nearby houses were also damaged.
Most of those killed were reportedly Houthis, but the Houthi-controlled Saba news agency reported that the casualties were civilians.
Saudi-led coalition launched an air campaign against Yemen in March 2015 in order to defeat the Houthis and restore Yemen's exiled government.
43 CHILDREN among the killed by airstrikes in Saada shopping center yesterday. #Yemen #اليمن pic.twitter.com/4hHQV1xg6U
— Yemen Post Newspaper (@YemenPostNews) 21 сентября 2015
Earlier, the UN said that about 5,000 people have already been killed in the violence, almost half of them civilians.
SEARCH for SURVIVORS: 28 killed, 49 injured by airstrike targeting civilians in public area of Hajja #Yemen #اليمن pic.twitter.com/hmOBBqh5sl
— Yemen Post Newspaper (@YemenPostNews) 21 сентября 2015
The Saba news agency has, meanwhile, reported that at least 236 people had been killed in air strikes in the past four days, including about 30 in the north-western province of Hajjah on Monday.
#Yemen: #KSA-airstrike in Alshagadera market Hajja province 28 civilians killed, pix https://t.co/v42AO1NVHS
— Dr Khalid Al-Shoba (@alshoba) 21 сентября 2015
Since the beginning of this year, Yemen has been pulled apart by violence between Houthi rebels, who forced the country’s government to resign, and supporters of Yemen's president-in-exile Abd Rabbuh Mansur Hadi.
Whole of Mufareh alKawkabani family perished in airstrike hit 6 homes & killed 25 day in alHasabah in Sana'a #Yemen pic.twitter.com/DWJ4gkxN3g
— Hisham Al-Omeisy (@omeisy) 22 сентября 2015
In late March, the Saudi Arabia-led coalition of nine Arab states began an aerial campaign against Houthi positions in Yemen at the request of the displaced leader. In late April, the coalition announced it would end its military operation in the country but the airstrikes have continued.