AT least three people were killed and 15 others wounded today after a bomb hit a Pakistani navy bus in the restive southern port city of Karachi, in the third such attack this week.

“A bomb planted on a roadside exploded when a Pakistan navy bus was passing by,” provincial government official Sharfuddin Memon said.

“A pedestrian was killed and 15 others were wounded,” Memon said of the attack which took place in the city’s busy Faisal avenue.

Naval officials said that a female doctor and a naval officer also died in the attack and nine other naval officials were wounded.

“One lady doctor and one officer were martyred in the attack and nine other officials were wounded in the bomb blast,” a senior naval official said.

Two security officials confirmed the attack.

Bomb attacks hit two buses carrying Pakistani navy officials in Karachi Tuesday, killing four people in the latest sign of rampant insecurity in a nation key to US hopes of winning its fight against the Taliban in Afghanistan.

Nearly 60 people were wounded in Tuesday’s attack when remote-controlled bombs exploded beside the buses at rush hour in different parts of Pakistan’s politically tense economic capital, used by NATO to ship supplies to troops in Afghanistan.

Karachi is home to Pakistan’s stock exchange and a lifeline for a depressed economy wilting under inflation and stagnating foreign investment.

But the city of 16 million is plagued by ethnic and sectarian killings, crime and kidnappings.

It is scored with rivalries between the Urdu-speaking majority and an influx of Pashtuns from the northwest, and outbreaks of political violence in Karachi killed more than 150 people last year.