A suicide bomber blew himself up at a checkpost in Mangora area of the valley, once a stronghold of Maulana Fazlullah, and his supporters, police sources told KUNA.
They said the explosion killed more than six persons and wounded several others.
There were also reports of two soldiers killed in the explosion but they could not be confirmed.
Police feared rise in the death toll as several wounded were said to be in critical condition.
The explosion occurred a day after military spokesman, Waheed Arshad, claimed that military troops have cleared almost all Swat valley of fighters in the operation that was launched after President Pervez Musharraf proclaimed emergency in the country.
Gen. Waheed said 290 fighters were killed in the operation and another 143 arrested in recent weeks. However, Fazlullah is on the run.
Güncelleme Tarihi: 09 Aralık 2007, 13:28