Twenty people were killed and 25 others injured in an attack on a bus taking pilgrims from Pakistan to Mashhad, Iran, to visit the Shrine of Imam Reza.

Reports indicate that a suicide bomber in a vehicle carrying explosives crashed into the bus in Pakistan's Baluchistan Province.

Eyewitnesses told a Pakistani television network that the explosion heavily damaged the bus that was carrying 40 pilgrims and also damaged a second bus close by.

Currently, no one has claimed responsibility for the attack. Fifteen percent of Pakistan’s population is Shia and a large part of them live in that country’s Baluchistan Province.

Extremist Sunni groups in Pakistan have carried out several attacks against the Shia minorities in recent years, and Human Rights Watch says that more than 300 Pakistani Shias have died in attacks carried out by Sunni extremists in that country in 2012.