At least 30 people died as violent weather swept the country on Friday and Saturday, and the threat isn't over.

Millions of Americans across the country are on alert for a severe weather outbreak as violent, long-track tornadoes with damaging winds of up to 80 mph and large hail are expected across the Midwest and South with the cross-country storm moving east.

Several tornado warnings have been issued in Missouri, while Georgia's governor declares a state of emergency.

Powerful storms with gusting winds and tornadoes have left at least 18 people dead in the Midwest and South of the United States.

Severe weather outbreak kills at least a dozen people as storms, tornadoes moved across the Midwest and South.