Gunmen opened fire on a passenger bus in the northern Pakistani district of Kohistan in an apparent sectarian attack today, killing 18 people.
"All the people on board were Shias, and at the moment it looks like they were targeted by armed men from the local Sunni community," a senior police official said.
The bus was travelling from central Pakistan city of Rawalpindi, near the capital Islamabad, to the northern town of Gilgit.
Police officials said the bus came under attack in an area inhabited by two Sunni tribes about 165km north of Islamabad.
The majority of Pakistanis are Sunni Muslims, with Shias accounting for about15 per cent of a population of 180 million.
Both communities largely live in peace with each other but militants from the two sides have killed thousands of people in tit-for-tat attacks since the beginning of Islamist militancy in the country in the 1980s.
Shia Muslims are a minority sect of Islam, arising from a dispute over the successor to the Prophet Mohammad 1,400 years ago. Many extreme Sunni Muslims consider them apostates.