Two explosions near electoral candidates' offices in Pakistan's southwestern province of Balochistan killed 28 people and wounded dozens yesterday, officials said, raising concerns over security on the eve of a general election.

Pakistan goes to the polls today amid rising militant attacks and the jailing of Imran Khan, the winner of the last national election, who has been dominating the headlines despite an economic crisis and other woes threatening the nuclear-armed country.

Authorities have said they are boosting security at polling booths. The first attack, which killed 18 people, took place at the office of an independent election candidate in Pishin district.

The second explosion in Qilla Saifullah, near the Afghan border, detonated near an office of Jamiat Ulema Islam (JUI), a religious party that has previously been the target of militant attacks, according to the province's information minister.

The deputy commissioner of Qilla Saifullah, Yasir Bazai, said that 10 people were killed and 25 wounded by a device planted on motorcycle parked near the office.

It was not immediately clear who was behind the attacks. Several groups, including the Islamist militant Pakistani Taliban (TTP) and separatist groups from Balochistan, oppose the Pakistani state and have carried out attacks in recent months.

"I'm appalled by today's terrorist attacks and condemn those seeking to prevent people from voting," British High Commissioner to Pakistan Jane Marriott said.

The attacks came as political parties wrapped up their campaigning in the quiet period mandated by electoral rules the day before the election.

The US State Department has voiced apprehension over observed challenges to freedom during Pakistan's current electoral process, reports Dawn online.

Deputy Spokesperson Vedant Patel, in a news briefing later on Monday, affirmed, "We want to see that process take place in a way that facilitates broad participation with respect for freedom of expression, assembly, and association."

Khan, in a message from jail, earlier urged his supporters to wait outside polling booths after casting their votes, as rival political parties held large rallies to mark the end of the election campaign period.

Any large-scale gathering of Khan's supporters near booths could raise tensions because of what they call a military-backed crackdown on him and his party that has restricted campaigning. The military denies interfering in politics.

"Encourage the maximum number of people to vote, wait at the polling station ... and then stay peacefully outside the Returning Officer's office until the final results are announced," said Khan on social media platform X, accompanied by an undated photograph depicting him wearing simple black clothing.

His Pakistan Tehreek-e-Insaf (PTI) party also released a video of Khan recorded just days before he was arrested in August, calling on people to turn out to vote.

Electoral frontrunner Nawaz Sharif led a huge rally in the eastern city of Kasur on Tuesday evening with his brother, former prime minister Shehbaz Sharif, who is running in that constituency.

Amid a sea of tens of thousands of supporters waving green party flags, Sharif called on the country's youth to support his party and took aim at Khan who has previously attracted support from young voters in the area.

"Don't fall for him," Sharif said.

Supporters of the rival Pakistan People's Party also gathered in the southern city of Larkana led by Bilawal Bhutto Zardari on Tuesday evening, who could play king-maker if no one party receives enough parliamentary seats to form a government outright.

The former foreign minister and son of assassinated prime minister Benazir Bhutto criticised opponents, including Sharif, for what he described as compromising the country's security and economy during their tenures.