A bomb attack targeting a Shia mosque in southwestern Pakistan has left at least 10 people dead and 12 others injured, officials say.

The incident occurred on Thursday in the town of Chalgari, located some 170 kilometers (105 miles) southeast of Balochistan’s provincial capital, Quetta.

Shia Muslims had gathered at the mosque to observe Muharram, the first month of the Islamic calendar, when a bomber blew himself up there, according to provincial home minister Sarfraz Bugti.

Bugti further said Pakistani authorities were transporting the victims to hospitals.

Mohammad Waseem, a local administration official, also confirmed Thursday’s attack as well as its death toll.

No one or group has claimed responsibility for the bombing so far.

On October 19, at least 10 people were killed in an explosion which targeted a passenger bus stationed at a terminal in Quetta.

Pakistani police officers guard a Shia procession during Muharram, the first month of the Islamic calendar, in Peshawar, October 22, 2015. ©AP

Pakistan’s troubled Balochistan Province has been the scene of several bomb and gun attacks over the past couple of years. Hundreds of Shia Muslims have been killed in militant attacks there.

The country’s Shia leaders have called on the Islamabad government to bring to justice those behind the ongoing bloodshed and targeted killings.

International organizations and regional countries have also expressed concerns over the killing of Shia Muslims across the Asian state.

Pakistan is facing security challenges after it joined an alliance with the US in the so-called war on terror. Thousands of Pakistanis have lost their lives and millions have displaced in bombings and militant attacks sweeping across the country since 2001.