A bomb blast has killed at least 14 people at an election campaign rally held by a pro-Taliban party in north-west Pakistan.
Javed Khan, a government administrator in the Kurram tribal region where the bombing took place, said the attack also wounded 50 people.
He said the bomb was apparently planted near the main stage of the rally.
Mr Khan said two party leaders escaped unhurt. No one immediately claimed responsibility for the blast.
The Jamiat-e-Ulema Islam party is considered to be supportive of the Afghan Taliban's fight against the United States and its allies. It is also sympathetic to the Pakistani Taliban.
The Taliban have in recent weeks attacked secular Pakistani parties. Elections are to be held on May 11.
One of the election candidates, Ainuddin Shakir, told a local television station that the blast went off just as the candidates were finishing their rally and leaving the stage. He said it appeared to have been detonated by remote control.
About 2,500 people had gathered at a local religious school to hear the candidates speak, said one man who was in the crowd, Sabir Gul. The massive explosion came just as one of the candidates ended his speech and was leaving the stage, he said.
Another resident, Mohammad Jamil, attended the meeting with his brother and was in the dining hall eating when the blast went off.
"There was a deafening sound which stunned me for a while but I quickly moved out of the dining hall," he said, describing a 'hell-like' situation. "There were countless people bleeding and crying for help. My brother Khalil was among them."
Interim Prime Minister Mir Hazar Khan Khoso condemned the bomb blast and called on the local government to strengthen protection for candidates in the upcoming election.
The historic vote, scheduled for this Saturday, will be the first time a democratically elected civilian government completes its term and hands over power to another. But the ongoing attacks against candidates, their supporters and political offices has cast a shadow over the momentous occasion, and may deter many people from going to the polls.
There is also concern that the attacks could benefit the parties that take a softer line toward the militants, because they are able to campaign more freely ahead of the vote. Monday's blast however showed that no side is immune from the violence. Maulana Fazlur Rehman, the head of Jamiat-e-Ulema Islam, has been an outspoken supporter of the Afghan Taliban, but some militants in Pakistan have shown a willingness to target anyone connected to the US-backed government in Pakistan.
In 2011, a suicide bomber struck a convoy in which Rehman was travelling through northwestern Pakistan, killing 12 people. The Taliban has also condemned democracy as a whole, meaning that any political party taking part in the elections could be considered fair game by the militant group.
The violence is multi-faceted and reflects the various militant problems facing the Pakistani government and military.
Most of the violence has come in the north-west, where Pakistan has been battling militants who are intent on overthrowing the government, and in the southern city of Karachi, where Taliban militants have gained a foothold. Numerous attacks have also hit candidates in the south-western Baluchistan province, where Baluch rebels are battling Pakistani troops.
On Sunday in the southern province of Baluchistan, two gunmen attacked a convoy of an independent candidate and killed two of his police guards.
On Friday, in Karachi, gunmen killed an anti-Taliban election candidate along with his six-year-old son and a political activist.