People transfer an injured man to hospital in southwest Pakistan's Quetta on July 13, 2018. (Xinhua/Irfan)

ISLAMABAD, July 14 (Xinhua) -- At least 105 people including a political leader were killed and over 150 others injured when a suicide blast hit a political meeting in Mastung district of Pakistan's southwest Balochistan province on Friday, officials said.

Confirming the death toll, caretaker home minister of Balochistan province Agha Umar said that the injured people are being treated at various hospitals.

Militant group of the Islamic State claimed the attack at its website.

Qaim Lashari, deputy commissioner of Mastung, said that target of the explosion was political leader Nawabzada Siraj Raisani, who was attending an election meeting in his constituency, Mastung, when the suicide bomber targeted him.

The leader, who lost his teenager son in 2011 to terrorism, was shifted to a hospital in neighboring provincial capital of Quetta where he succumbed to injuries.

Raisani, a candidate of Balochistan Awami Party, was vying for a seat in the provincial assembly.

The bomb disposal squad said that an estimated 18 to 20 kg of explosive materials were used in the explosion.

Lashari said that the death toll is feared to further rise as 22 among the injured people are in critical condition.

The country's President Mamnoon Hussain, caretaker Prime Minister Nasir-ul-Mulk and army chief Qamar Javed Bajwa condemned the attack.

Friday's attack was the third and the deadliest attack during the recent spate of terrorist attacks targeting political leaders who are busy in holding meetings and addressing public gatherings ahead of general elections to be held in the country on July 25.

The attacks left over 130 people killed and over 200 injured during the last three days.

Earlier on Friday afternoon, four people were killed and 40 others wounded when a remote controlled blast hit the convoy of a former chief minister and election candidate in his constituency in Khyber Pakhtunkhwa province.

Earlier on Tuesday night, a suicide blast hit a political leader's convoy in the country's northwest Khyber Pakhtunkhwa province. The country's senate was on Friday told that the blast left 22 people including the leader killed and 75 others injured.

After Friday's blast, the country's election commission canceled election in Mastung constituency. As according to the country's constitution if candidate of some constituency dies, the polls in the particular area are terminated.