QUETTA: Gunmen shot dead 26 Pakistani Shia Muslim pilgrims travelling to Iran on Tuesday, the deadliest attack on the minority community in Pakistan for more than a year, officials said.

In a brutal assault, gunmen ordered pilgrims off their bus, lined them up and assassinated them in a hail of gunfire in Mastung, a district 50 kilometres (30 miles) south of Quetta, the capital of the southwest Baluchistan province.

An hour after the first attack, unidentified gunmen killed another three Shias on the outskirts of Quetta whom police said were relatives of victims of the first incident en route to collect their bodies.

“The attackers stopped the bus and forced the pilgrims to get off, lined them up and then opened fire,” local deputy commissioner Saeed Imrani told AFP, referring to the first attack.

“The death toll has risen to 26. At least six people were wounded, four of them are in a critical condition,” he added, after earlier saying 20 died.

Referring to the second incident, Hamid Shakil, a senior police officer in Quetta, told AFP by telephone: “Armed men ambushed their car. Three of them were killed and one was wounded. They were going to take the dead bodies.”

Much of Pakistan, a key US ally in the war on Al-Qaeda and the 10-year fight against the Taliban in neighbouring Afghanistan, suffers from near daily  militant violence.

Baluchistan has increasingly become a flashpoint for sectarian violence between Pakistan's majority Sunni Muslims and minority Shias.

The attack, confirmed as sectarian in nature by Pakistani officials, was the deadliest on Shias in Pakistan since September 4, 2010 when a suicide bomber killed at least 57 people at a Shia rally in Quetta.