CHICAGO (AFP) - The deadliest tornado to hit the United States in more than 50 years cut a deadly swath through a Missouri town, turning homes into rubble, destroying a school, ripping apart a hospital and killing at least 99 people. The tornado struck the town of Joplin near the border with Oklahoma and Kansas on Sunday evening, less than a month after a horrific tornado outbreak left 354 dead across seven US states. It was the deadliest of 46 tornadoes reported to the National Weather Service in seven states on Sunday. Its a war zone, Scott Meeker of the Joplin Globe newspaper told AFP. Weve got hundreds of wounded being treated at Memorial Hall (hospital), but they were quickly overwhelmed and ran out of supplies, so theyve opened up a local school as a triage centre, Meeker said. The White House said in a statement Monday that President Barack Obama has been monitoring reports about the devastation and the rescue efforts during his flight overnight Sunday to Ireland. People in Joplin clawed through the rubble looking for friends, family and neighbours after the storm tore buildings apart and turned cars into crumpled heaps of metal. Flames and thick black smoke poured out of the wreckage of shattered homes, and water gushed out of broken pipes as shocked survivors surveyed the damage, early photos showed. A tangled medical helicopter lay in the rubble outside St John Regional Medical Centre, which took a direct hit. Jeff Law, 23, was able to take shelter in a storm cellar and was overwhelmed by what he saw when he emerged. Ive lived in this neighbourhood my entire life, and I didnt know where I was, Law told the Springfield News-Leader. Everything was unrecognizable, completely unrecognizable. Its like Armageddon. The emergency manager at the neighbouring county of Springfield-Greene was told that at least 24 people were killed before he rushed over to help, a spokeswoman told AFP. With many phones down in the area, it was difficult to get further confirmation. Its so devastating we cant even grasp it at this point, Rob Chappel of the Jasper County coroners office told AFP.