As campaigning intensifies, attacks in different areas of the country have stoked fear of more violence in the Muslim country of 208 million where political rallies can draw tens of thousands of people.

The July 25 election features dozens of parties, with two main contenders: ex-cricket hero Imran Khan's Pakistan Tehree-i-Insaf and the Pakistan Muslim League-Nawaz, which vows to win a second term despite the jailing of founder, ex-Prime Minster Nawaz Sharif, on a corruption conviction.

Islamic State claimed responsibility for Friday night's suicide bombing at a rally for the Baluchistan Awami Party (BAP). Among the 130 killed was the party's provincial assembly candidate Siraj Raisani.

A video clip showed Raisani speaking just before the attack, greeting crowds seated on the ground under a large tent before the blast hit and the image cut off.

A senior party official said the attack would not dent its election hopes. "It's a big loss as far as Mr Raisani is concerned for us ... But will it reverse the course of the political party? No," said Anwar ul Haq Kakar, a BAP member of Pakistan's Senate.

Pakistan's campaign until this week had been relatively peaceful, compared with frequent attacks by the Pakistani Taliban during the 2013 election, which saw 170 people killed, according to statistics from the Pakistan Institute for Peace Studies.

Then, three attacks over four days killed at least 152 people.

On Tuesday, a Pakistani Taliban suicide bomber blew himself up at a rally by the Awami National Party (ANP) in the northwestern city of Peshawar, killing 20 people.

And on Friday, another bomb struck the convoy of the religious Muttahida Majlis-e-Amal party (MMA) in the northern town of Bannu, killing four people.

Although overall violence has ebbed in Pakistan in recent years following an army offensive on militant strongholds in the northwest, both the Pakistani Taliban and Islamic State still launch attacks from across the border in Afghanistan.

Australian Associated Press