ahmed al-karim , head of the salahuddin provincial council , said the fighters had burnt ` hundreds of houses ' in the last two days .
it comes as prime minister haider al-abadi ordered iraqi forces to oppose vandalism in the city of tikrit , retaken from the islamic state group this week .
mr karim , who left for baghdad late on friday afternoon due to the chaos , said houses and shops were being burnt and fighters from inside them .