Insurgents detonated two voting centers near the flashpoint Iraqi city of Fallujah on late Wednesday, 12 hours after they were opened, witnesses said Thursday.

"US troops opened two voting centers in Ameriyat al-Fallujah, some 7 km southwest of Fallujah. The two centers were nothing but two shops which were detonated 12 hours after being opened," the witnesses told Xinhua.

Moreover, US tanks called on Fallujah residents through loudspeakers to go to the US base on Sunday to vote after it seems impossible to open election centers in the city, according to the witnesses.