WASHINGTON (AFP) – A powerful tornado ripped through an Oklahoma City suburb Monday, striking at least two elementary schools and leveling block after block of homes, according to US news reports.

Reporters on the ground for local television station KFOR saw school pupils as young as nine being “pulled out” of one school in Moore, a residential community of 55,000 to the south of Oklahoma’s state capital.

An unknown number of children were feared trapped inside the Plaza Towers school, where anxious parents were being kept at a distance while search and rescue workers scrambled to free the pupils.

From its news helicopter, KFOR’s cameras captured scenes of widespread destruction throughout Moore, with street after street of homes stripped of their roofs and cars piled atop each other like toys.

Storm spotters estimated the tornado, which struck in mid-afternoon, to be as big as two miles (3.2 kilometers) wide. It briefly dissipated, only to recycle to the east of Oklahoma City, threatening the town of Meeker.

“We anticipate that these storms are going to continue to build around Oklahoma,” a grim Governor Mary Fallin told CNN, as the National Weather Service urged residents to take cover.

In downtown Oklahoma City, tornado sirens went off at least three times.

In Moore, live images from KFOR showed people wandering among the debris and even a couple of untethered horses from a local stables that somehow managed to survive the punishing storm.

“I had no idea it was coming,” said a stable worker, who told how he survived the “unbearably loud” twister by taking cover in one of the stalls.

Tornadoes frequently touch down on Oklahoma’s wide open plains, but the fact that Monday’s twister struck a populated urban area raised fears of a high casualty toll.

On Sunday, a powerful storm system churning through the US Midwest spawned tornadoes in Iowa, Kansas and Oklahoma, destroying homes and killing at least two people, US media reported.