Description:Flags were lowered in the Pakistani city of Quetta --- as locals mourned the 81 people killed in a bombing the previous day. Many Shi'ites are frustrated with the city's escalating violence --- and accuse the government of turning a blind eye to extemists. There were similar demonstrations throughout the country. In Karachi, around four hundred angry protesters set a bus and a water tanker on fire as they marched through the streets of the port city .(0:40)