At least 16 people killed in Yemen's mosque bomb attacks - sources
The mosques are known to be used mainly by supporters of the Shi'ite Muslim Houthi group which has seized control of the government.
Yemen is torn by a power struggle between the Iranian-backed Houthis in the north and the U.N.-recognised President Abd-Rabbu Mansour Hadi, who has set up a rival seat in the south with Gulf Arab support.
(Reporting by Mohammed Ghobari; Writing by Rania El Gamal; Editing by Hugh Lawson)