At least seven people have been killed and 13 injured in a suicide attack on an election candidate in north-western Pakistan, officials and witnesses say.
They say that the attack took place in the tribal area of North Waziristan, on the border with Afghanistan.
It is the second attack on the Awami National Party (ANP),a Pashtun nationalist group, in three days.
On Saturday, a suicide bomber struck at an ANP rally in the Charsadda district of the North West Frontier Province.
More than 20 people were killed in that attack.
Meanwhile, lawyers across the country have launched a boycott of courts until the elections and held.
They staged protests inside courtrooms in major cities to call for the restoration of the country's deposed Chief Justice, Iftikhar Muhammad Chaudhry.
Monday morning's bomb attack took place in the village of Eidak, in North Waziristan's Mir Ali subdivision, officials of the local administration told the BBC Urdu service.
They said that the attacker rammed a car laden with explosives into the vehicle of an election candidate who was in a convoy going to a public meeting.
North Waziristan has been the scene of recent fierce clashes
The candidate, Nisar Khan, escaped unhurt in the attack, but some important ANP local leaders were killed, according a local journalist who witnessed the attack.
The BBC's Ilyas Khan in Karachi says that this is the first attack on the ANP leadership in the tribal areas, where the party has traditionally commanded considerable support.
Our correspondent says that the ANP has become the target of Islamic militants, themselves predominantly ethnic Pashtun, because of its secular and progressive politics.
Political parties are not allowed to operate in the semi-autonomous tribal areas of Pakistan, but all parties have a presence there through unofficial organisations.
Our correspondent says that is why Nisar Khan, a member of the ANP, was contesting as an independent candidate.
In a separate development, lawyers across the country continued with their protest against former Chief Justice Chaudhry's dismissal.
In Karachi, the country's biggest city, hundreds of lawyers gathered around the main courthouse while judges stayed in their chambers.
They say they will remain on strike until the elections on 18 February.
"The establishment's attitude toward lawyers is getting harsher and harsher day by day," Nahid Afzal, a senior lawyer, told the Associated Press news agency.
"They cannot foil our struggle."
Lawyers have been at the forefront of public protests against President Musharraf as the country prepares to elect a new parliament.
The president needs a commanding majority in the legislature to block any impeachment moves.