Sindh Home Minister Dr. Zulfiqar Mirza said Tuesday government had foiled a conspiracy to spread ethnic violence in the metropolis. Addressing a press conference, he said four suspected persons have been held in connection with the series of blasts, killing at least one and injuring more than 40 people in Karachi on Monday. Mirza said bombs used in Karachi were of low intensity. Blasts injured 43 people and six to seven persons were yet under treatment in different hospitals, he added.