Media reports say two bomb explosions near candidates' offices in the Pakistani province of Balochistan killed at least 28 people and wounded dozens on the eve of general elections, officials said.

The BBC says the first blast killed 16 people in Pishin district, north of Quetta city.  The second explosion reportedly left 12 people dead in Qila Saifullah to the east.

The Islamic State (IS) terrorist group reportedly said it was responsible for both attacks.  It said both of Wednesday's bombings were carried out using motorbikes rigged with explosives

Al Jazeera reports that in the immediate aftermath of the dual attacks, Pakistan’s foreign office said in a statement that its western border crossings with Iran and Afghanistan would close until Friday to ensure security during the election.

UN Secretary-General Antonio Guterres condemned the bomb attacks, his spokesperson Stephane Dujarric said.

“We strongly condemn the horrific attacks, and the bomb explosions that we saw earlier today that killed many, many people and injured many more a day before the elections, clearly related to the elections,” Dujarric said.

Balochistan is Pakistan's largest and poorest province, having a history of violence.  It has seen a decades-long struggle for greater autonomy by various groups, some of them armed.  Islamist militants, including the Pakistani Taliban (TTP), operate along the border with Afghanistan.