NEW YORK
The US state Oklahoma City was hit by a monster tornado, which killed at least 51, 20 of whom are school pupils, officials said.
City of Moore, a suburb of 55,000, was the worst affected area. Plaza Towers Elementary school in the city was hit directly by the storm, where 7 bodies of school children recovered and 24 are still missing.
At its strongest, the tornado reached speeds of up to 320 km and a width of about 3.5 km.
President Barack Obama has declared a 'major disaster' in Oklahoma, ordering federal aid for the state.
Search-and-rescue efforts will continue throughout the night, officials said.
Moore was hit by a series of major tornadoes on May 3, 1999, which left 40 people dead and caused a damage of over $1 billion.
