MOORE, Oklahoma (AFP) - Severe thunderstorms barrelled through this Oklahoma City suburb at dawn on Thursday, complicating clean-up efforts three days after a powerful tornado killed 24 people and destroyed 2,400 homes.

More rain was forecast to fall on Moore, soaking the disaster zone where residents had just the day before, under clear blue skies, started picking through the rubble of their destroyed houses to recover personal effects.

Localised street flooding was liable to upset access for emergency and clean-up vehicles.

Monday's exceptionally strong tornado - one of the worst in recent years in the United States - killed 24 people, including two infants and seven pupils trapped inside their collapsed elementary school.

The Oklahoma Department of Emergency Management said 2,400 homes had been damaged and 10,000 people affected, in a community of 56,000 that was hit by an even deadlier twister in May 1999.

Late Wednesday, Governor Mary Fallin's office updated the number of injured to 353, from 237 earlier, and said that "all people thought missing have been accounted for at this time".