A suicide bomber has killed at least three paramilitary forces and left another 21 wounded in southern Pakistan when he rammed his vehicle into the gates of a military base.

Thursday's blast targeted a Rangers paramilitary headquarters in Karachi and is the latest in a series of attacks against security forces, said Javed Odho, Karachi police inspector general.

Al Jazeera's Kamal Hyder, reporting from Islamabad, said the Pakistani Taliban issued a statement saying they carried out the attack on the headquarters of the paramilitary base in the nation's largest city.

"The target was the residential quarter ... The purpose of the attacker would have been to get to as many people in that residential quarter as possible", said our correspondent.

The police investigation team said more than 100 kilogrammes of explosives were packed into the small truck that rammed into the building.

The Rangers paramilitary forces have been aiding Karachi police in anti-terrorism operations.

The Tehrik-e-Taliban Pakistan, TTP, had previously issued a statement saying they would target the Muttahida Qaumi Movement, MQM, a political party in Sindh province with a large presence in Karachi.

Al Jazeera's Hyder said the statement was proof the Pakistani Taliban made Karachi into their "next battleground".

Source: Al Jazeera And Agencies