Armed men in northern Pakistan have shot dead at least 22 members of the Shia sect of Islam, an official says.
The victims were travelling on board three buses in the Naran Valley when they were forced to step off the vehicles and were shot dead, security officials told Al Jazeera.
The attack took place near Babusar Top, on the border between Mansehra and Gilgit districts on Thursday.
It was carried out by at least 10 assailants, security officials told Al Jazeera.
"After checking [their] papers, [the attackers] opened fire," said Khalid Omarzai, the local administration chief in Mansehra. Shafiq Gul, a police official, said that the gunmen were masked, while Omarzai said that they were wearing military fatigues.
Ali Sher, the deputy inspector-general of police in Gilgit, said the victims were travelling from Rawalpindi, near the capital Islamabad, to Gilgit, a mostly Shia area.
A statement issued by the office of UN secretary-general Ban Ki-moon said he was "appalled" by the sectarian killings.
"The secretary general expresses his outrage over such deliberate attacks on people due to their religious beliefs in Pakistan," the statement, issued by Martin Nesirky, UN spokesman, read.
Gilgit is a popular tourist destination for wealthy Pakistanis and expatriates who live in the country, but has seen an increasing number of sectarian attacks in recent months. Sunni extremists who have carried out such attacks say that Shia Muslims are not true members of the faith.
On February 28, gunmen in military fatigues killed 18 Shias in a similar attack in Kohistan, on the same bus route.
On April 3, a Sunni mob dragged nine Shias off buses and shot them dead in the town of Chilas, about 100km south of Gilgit.