ISLAMABAD, Pakistan -- At least 43 people were killed and 13 injured Wednesday in the southern port city of Karachi when gunmen attacked a bus full of Ismaili Shiite Muslims, a small minority community in Pakistan.
The attackers burst into the bus near the busy Safoora Square, in a congested part of Karachi, and shot the passengers at close range, a Pakistani government official in Karachi told CBS News on condition of anonymity.
Ghulam Haider Jamali, chief of police of the southern Sindh province of which Karachi is the local capital, told reporters there were 60 passengers in the bus.
"The gunmen used 9 mm pistols in the attack which killed at least 43 people" said Jamali. The gunmen fled after the attack. Jamali said 16 women were among the dead.
"This was one of the most brutal attacks in recent memory. The tactic is comparable to the December attack on the school in Peshawar," said the official, drawing comparisons to a Taliban attack in the northern city which left 141 people dead, mostly students.
There were no immediate claims of responsibility for Wednesday's attack.
The government official told CBS News there had been reports recently that the Taliban or one of their affiliates were planning a major attack in the city. The Taliban are Sunni Muslims, and they have often targeted Shiites in Pakistan.
"Karachi is a big city with a population of more than 20 million. There were alerts but it was impossible to pinpoint where and in what manner the attack will come," said the official, who was not authorized to speak to the press.
Concern over the safety of Western nationals in Karachi has been running high since the mid-April attack on Debra Lobo, an American woman who worked at a private medical school in the city.
Politicians from across Pakistan's political divide condemned the attack and promised to continue supporting the ongoing army-led campaign against Taliban militants and their associates.