ISLAMABAD, Pakistan, Feb. 29 (UPI) -- The 18 bus passengers shot and killed by gunmen in northwestern Pakistan's Kohistan district apparently were victims of sectarian violence, local police said.
In the attack Tuesday in the relatively calm mountainous district in the Khyber-Pakhtunkhwa province, the gunmen ambushed four passenger buses, ordered some of the males out and shot and killed 18 of them, CNN reported, quoting police.
The buses were attacked as they traveled from the garrison town of Rawalpindi to Gilgit city, which has a large population of Shiites Muslims who are a minority in the Sunni Muslim-majority Pakistan.
CNN quoted a police official as saying the gunmen picked out the male Shiite passengers, lined them up and shot them. He said eight others were injured, but the Sunni passengers were not harmed.
Pakistan has seen much sectarian violence targeting the Shiite minority in other parts of the country.
Pakistani officials condemned the attack and President Asif Ali Zardari said those responsible for "such a heinous crime will not be spared."
Police official Khurshid Khan said this was the first time such a major incident had occurred in Kohistan where Sunni-Shiite violence had been minimal, CNN reported.
Pakistani Interior Minister Rehman Malik announced the formation of a team to investigate the incident, the state-run Associated Press of Pakistan reported.
Muhammad Amir Rana, who heads an Islamabad think tank, told CNN that rising sectarian tensions lately between the Sunnis and Shiites in Kohistan have led to a number of targeted killings.
Pakistan's Express Tribune quoted sources as saying an outlawed terrorist group had claimed responsibility for the latest attack.
The report quoted a police official as saying the gunmen did not target women or children passengers.
At the United Nations, Secretary-General Ban Ki-moon condemned the "abhorrent" bus attacks and expressed his condolences.
"The United Nations stands by Pakistan in its efforts to combat the scourge of terrorism and extremism, which continues to claim the lives of so many Pakistanis," his statement said.