Unidentified gunmen in Pakistan have killed six members of the main opposition Pakistan People's Party (PPP), police say.
The PPP is gearing up for elections
They say that two other people were wounded in the attack.
The attack took place in the town of Attock, 120kms (57 miles) west of the capital, Islamabad.
A general election is due in Pakistan in late 2007 or early 2008, and rival political parties have already begun manoeuvring for support.
Correspondents say that Pakistani elections are traditionally plagued by violence between rival supporters.
"We do not know what the motive is behind the attack. We are investigating," police spokesman Najab Khan told the AFP news agency.
Ms Bhutto has been told she cannot take part in the vote
PPP spokesman Farhatullah Babar said the attack was meant to frighten party workers there.
"It seems to us that now the elections are near, a message has been sent to the PPP supporters to desist from supporting the party," Mr Babar told AFP.
"We demand the arrest of the culprits. One of the men murdered in the attack was a local office-bearer (a party leader at village level)," he said, adding the dead included three brothers.
Correspondents say that three PPP workers were killed in the same district during the by-elections in 2004 when the current Prime Minister, Shaukat Aziz won a national assembly seat.
The PPP is led by former Prime Minister Benazir Bhutto who has lived in self-imposed exile since 1998.
She has said she that will return for the election, although President Musharraf has warned that she will not be allowed to compete in the vote.
He has accused her of corruption during her time in office, but she denies the allegation.