(Adds nine wounded) BAGHDAD, Jan 31 (Reuters) - A fuel truck blew up at an Iraqi army base in Miqdadiya on Wednesday in what police and army sources said was a suspected suicide attack that wounded at least nine people. An army source said the vehicle rammed the main gate of the base in the town 90 km (50 miles) northeast of Baghdad and preliminary reports were of nine wounded. Residents said the explosion caused a huge ball of fire and a loud blast that was heard throughout the town. Miqdadiya is in the restive province of Diyala where sectarian violence between Shi'ites and Sunni Arabs has caused relentless bloodshed and where insurgents often attack U.S. forces.