Tanzanian police arrested nine suspected members of the al-Qaeda linked al-Shabaab group at a local mosque in the Kilombero district in the south west of the country.
A 10th person was stoned by witnesses after he attacked the arresting officer, Police Commissioner Paul Chagonja said by phone. Those arrested are Tanzanian nationals and were carrying explosives, he said.
Al-Shabaab has led an eight-year insurgency to oust the Somali government and establish a strict version of Shariah, or Islamic law. The east African region is facing a growing threat from cross-border attacks by the Islamist militants.