At least six demonstrators were killed in Bangladesh during violent clashes between rival student groups over quotas for coveted government jobs, police said, a day after more than 100 others were injured. Police fired tear gas and rubber bullets as university students battled with counter-protesters backing the ruling Awami League party, fighting with sticks and hurling rocks. The violence marks an escalation in efforts to hinder a determined weekslong campaign of sit-in protests and street marches that has ignored calls by Bangladesh's prime minister and top court for students to return to class.