The sectarian conflict in Pakistan between the dominant Sunni Muslims and minority Shias has taken another deadly turn after armed gunmen murdered at least 20 Shia Muslim migrant workers returning home on a bus after celebrating the Islamic festival of Eid.

The Daily Telegraph newspaper of Britain reported that three buses were intercepted by masked men wearing military uniforms in the district of Manshera, a resort area in northern part of the country.

The gunmen checked the passengers’ travel documents, separated the Shias from the others, marched them outside and executed them at point-blank range, according to local police officials.

“Ten to 12 people wearing army uniform stopped the bus and forced some people off the bus,” said Khalid Omarzai, administration chief in Mansehra, according to Dawn, the Pakistani newspaper.

“After checking their papers, they opened fire and at least 20 people are reported to have been killed. This is initial information and the final toll may go up. They are all Shias.”

Dawn reported that Shias have protested the killings by burning tires and blocking roads in the region, which is popular with wealthy tourists and foreign mountaineers.

The chief minister of Gilgit-Baltistan, Syed Mehdi Shah, has called an emergency meeting of his top aides and demanded the immediate arrest of the killers.

In February of this year, in an eerily similar incident, masked gunmen removed 18 Shias from buses outside the town of Chilas (in the same region as the recent massacre) and murdered them in cold blood.

“Both attacks are identical in method, so it’s clear that they were carried out by the same militant groups, if not the same people,” Farooq Ahmed, editor of the Mountain Times, told the Telegraph.

Pakistan is a predominantly Sunni Muslim state, although it has a sizable Shia minority – estimates range from 5 percent of the population to as high as 25 percent.

Shias, like other religious and ethnic minorities, have long suffered discrimination in Pakistan, but the sectarian violence between Shias and Sunnis is a relatively recent phenomenon.

Pakistan media and government figures have alleged that Shia extremists in the country have been supported and funded by Iran (a Shia state).