Five unidentified persons riding motorcycles first lobbed two grenades outside the Mobina Town police station in which one policeman was injured and several vehicles were damaged, police said.
The same people then threw two more hand grenades near a girls' College in Karimabad, damaging the boundary wall of the institution.
"All three attacks took place within a span of two hours that is why we suspect the same gang is involved," said Mushtaq Sukhera, Karachi police chief.
"These are basically attempts to spread panic and fear as the operation against terrorists and militants has been stepped up in Karachi," Sukhera said.
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