Police said the suspected extortionists lobbed hand grenades at Zain medical clinic in Muzaffarabad colony of Landhi area yesterday and the resulting explosion killed one woman and injured five.
"The clinic had been receiving threatening calls after being told to pay extortion money sometime back but the matter was not reported to the police," one official said.
He added that unless extortion cases were reported to the police, adequate security was impossible to provide.
The law enforcement agencies have been carrying targeted operations in Pakistan's biggest city and financial hub since last month to rid of militants and criminals in the metropolis. The paramilitary rangers arrested 15 people in Karachi yesterday.
