Thirteen people were killed in violence across Uttar Pradesh over the centre's new citizenship law, which broke out after Friday prayers. One person had died in Lucknow and one in Sambhal on Thursday, taking the total number of deaths in the state to 15. The police said four persons have died in Meerut, two each in Firozabad and Bijnor, one each in Sambhal, Kampur, Varanasi and Lucknow.