A number of North Texas counties are under a Tornado watch, with witnesses reporting that twisters have already touched down in some places, accompanied by golf-ball size hail.

There are confirmed reports in the eastern town of Azle and also extensive damage in Saginaw.

The concern, however, is that the storm moves its way eastward and hits the heavily populated city of Dallas and the Fort Worth International airport. Tornado warnings are in effect for Dallas and Tarrant counties until 8:45 p.m.

The twister follows one that that just wreaked havoc on the small town of Joplin Missouri, killing 117 people -- one of the deadliest on record.

More deaths have resulted from outbreaks of multiple tornadoes.

On April 27, a pack of twisters roared across six Southern states, killing 314 people, more than two-thirds of them in Alabama.

Speaking from London, President Barack Obama said he would travel to Missouri on Sunday to meet with people whose lives have been turned upside down by the twister.

The American people are by your side, Obama said. We're going to stay there until every home is repaired, until every neighborhood is rebuilt, until every business is back on its feet.

The National Weather Service has issued a tornado watch for Collin, Cooke, Dallas, Denton, Grayson, Jack, Montague, Palo Pinto, Parker, Rockwall, Tarrant and Wise counties until 10 p.m.