Five women were among those killed in what effectively was the resumption of heavy bombardment by the Saudi-led alliance targeting Yemen's Shiite rebels and allied forces loyal to Yemen's ousted president. The resumption comes after UN peace talks on Yemen collapsed over the weekend in Kuwait.
The airstrikes also signal the end of a fragile truce declared by the United Nations in April to pave the way for peace talks.
Since the Saudi-led coalition launched airstrikes against the Houthis, the war has claimed 9,000 lives, displaced some 2.4 million people and pushed the Arab world's already impoverished country to the verge of famine.
The bombing of the factory located in western Sanaa is one of series of airstrikes that rocked the capital and at least five other provinces, presumably targeting suspected rebel positions such as barracks housing Houthis and their allies, ousted President Ali Abdullah Saleh's forces.
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Photographs posted by activists on social media show torn and charred bodies at the location. The same factory was hit in airstrikes in January, though there are no visible Houthi camps or barracks in the vicinity of the factory. The nearest rebel post is nearly 1.5 kilometres away.
The factory official and the medics spoke on condition of anonymity, fearing retribution by the Houthis.
Yemen's SABA news agency, which is now under Houthi control, said dozens of airstrikes pounded Sanaa, the Houthis' northern stronghold of Saada, the western cities of Taiz and Jouf, and the Red Sea ports of Makha and Houdeida over the past 24 hours.
Since the start of two-year war, the Saudi-led coalition has controlled of the airspace over neighboring Yemen.