A suicide bomber killed at least one person when he rammed his vehicle into the gates of a military base in Pakistan's largest city on Thursday, police said, the latest in a series of audacious attacks on security forces.
Thirteen people were wounded in the explosion but the attacker was unable to penetrate into the headquarters of the Rangers paramilitary base in the port city of Karachi.
"It is a heavy blast near the Rangers office, with some casualties," said senior police official Javed Odho.
He told Pakistani television the bomber had used more than 100 kg of explosives in the attack. Karachi is Pakistan's financial hub and is home to 18 million people.
The bombing is the latest in a series of attacks on military bases in Pakistan, including a 16-hour assault on Pakistan's navy base in Karachi in 2011 that killed at least 10 people and an attack on the army headquarters in Rawalpindi in 2009.
Some of the assaults have prompted speculation the attackers had sympathizers inside the military who gave them information about the bases.
Nuclear-armed Pakistan, an uneasy US ally, is fighting its own homegrown Taliban as well as other insurgents who cross its porous border with neighboring Afghanistan.
Karachi is home to a number of sectarian groups and fighters allied to the Taliban insurgency and is also faced with an epidemic of violent crime.