HOUSTON -- A tornado struck south of Oklahoma City on Monday afternoon, ripping apart buildings in populated areas, U.S. media reported.

Areas of metropolitan Oklahoma City appeared to be in shreds Monday afternoon after the massive tornado moved through the region, according to CNN. "The houses are destroyed. ... Completely leveled," a helicopter pilot was quoted as saying.

A school was among the buildings leveled by the tornado, according to the report. The U.S. National Weather Service had issued a rare tornado emergency for the Oklahoma City metropolitan area, meaning that significant and widespread damage and fatalities were likely, CNN reported.