Hundreds of thousands of Bangladeshi protesters demanding Prime Minister Sheikh Hasina resign clashed with government supporters Sunday, with scores killed in one of the deadliest days since demonstrations began.

Rallies that began last month against civil service job quotas have escalated into some of the worst unrest of Hasina's 15-year rule and shifted into wider calls for the 76-year-old to step down.

At least 77 people were killed on Sunday, alone, including 14 police officers, with the rival sides battling with sticks and knives and security forces firing rifles, taking the total killed since protests began in July to at least 283.