Nine people were injured on Monday when suspected militants attacked the office of National Party (NP) in Balochistan's Turbat district, police officials said.
The attackers lobbed a hand grenade inside the NP office targeting the workers inside, officials said.
Three NP workers were seriously injured whereas three others suffered minor injuries. The blast also caused damage to the office.
Two of the injured have been referred to Karachi for medical treatment.
The president of National Party, Senator Mir Hasil Bizenjo has condemned the incident and termed it as an act of terrorism.
"We will not bow down before the elements playing in the hands of foreign powers," said Bizenjo.
The assailants escaped unhurt from the spot and no one has claimed the attack so far.
Security personnel and workers of Baloch nationalist parties have been frequent targets of attacks in Turbat in the past few years, with several of these orchestrated by Baloch separatists and sectarian outfits.