The attack in Ziarat Masood village of Mohmand district came a day after war planes bombed a militant stronghold.
"A group of militants attacked houses of Malik Ghazi Khan and Malik Ghulab Khan, who were also members of a local peace committee, killing six people and wounding four others," local administration official Zabit Khan told AFP.
He said the militants, said to number up to 70 and armed with rockets, hand grenades and Kalashnikov rifles attacked the two houses late Sunday.
"Those killed in the attack also included close relatives including sons of the two tribal elders," he said.
Of the two elders, Malik Ghazi Khan sustained injuries while Malik Ghulab Khan was not present at the time of attack.
Another local official confirmed the casualties and said "the attack might be a reaction to the ongoing military operation in Mohmand".
Local troops launched an air and ground operation to evict militants from the stronghold of Walidad in Mohmand on Saturday, killing 25 rebels.
Copyright AFP (Agence France-Presse), 2011