MQM Pakistan leader Khawaja Izharul Hassan was the target of an assassination attempt early Saturday morning in Karachi's Buffer Zone area.
Hassan, who is the leader of the opposition in the Sindh Assembly, escaped unhurt, but at least four others are reported to have been injured in the attack.
MQM Pakistan leader Faisal Sabzwari tweeted that the attackers wore police uniforms. He said three of Hassan's police guards took bullet injuries of whom one, a police constable, was killed in the attack. A teenager was also killed in the cross-fire.
One of the assailants was shot dead in retaliatory firing, police said, while another was injured but managed to flee. Police also said they had recovered a 9mm pistol and a motorcycle used by the killed attacker from at the scene of the incident.
DawnNews quoted police officials as saying that assailants on three motorcycles had attacked the politician after he left a mosque in Buffer Zone for home after Eidul Azha prayers.
Condemnations poured in from provincial lawmakers soon after the attack. The city's police chief was also directed to submit a report on the matter.
MQM Pakistan supremo Farooq Sattar later said in a press conference that the provincial government cannot be absolved of responsibility in the incident.
"What if the leader of the opposition had been killed? What would have the city's situation have been like?" he said. "Already, people are frustrated with the way Karachi was completely neglected in the aftermath of the [recent] rains."
Sindh Chief Minister Murad Ali Shah also condemned the attack and demanded a detailed report from Sindh Inspector General of Police A.D Khowaja.