PESHAWAR, Pakistan — Police say a suicide bomber attacked a volleyball tournament today in a northwest Pakistani city near the insurgent-riddled tribal areas.

At least eight people were wounded in the blast in Lakki Marwat.

Local police Chief Ayub Khan says the blast might have been retaliation for local officials' attempts to expel militants by setting up their own militia. He says some nearby houses have collapsed, and that other people might be trapped in the rubble.

Lakki Marwat is close to North and South Waziristan, two tribal regions where militants have proliferated.

Since the army launched a ground offensive in South Waziristan in October, a slew of bombings have plagued Pakistan and killed more than 500 people.