Oklahoma tornadoes kill at least five

· At least five people were killed when tornadoes slammedOklahoma Cityand its suburbs.

· Some 40 to 50 people were being treated forstorm-related injuries.

·The storm crumbled cars and tractor-trailers along amajor interstate highway and caused havoc.

HOUSTON, June 1 (Xinhua) -- The Oklahoma authorities confirmed on Friday that atleast five people were killed when tornadoes slammed Oklahoma City and its suburbs where are stillrecovering from a monster twister less than two weeks ago.

The Oklahoma HighwayPatrol said earlier a mother and her baby were killed in their car whiletraveling on Interstate 40, just west of Oklahoma  City.

The Oklahoma MedicalExaminer's Office said two of the deaths occurred in Union City and one was in El Reno, west ofOklahoma City.

Some 40 to 50 peoplewere being treated for storm-related injuries, including five patients incritical condition, among them a child, according to the Integris Health hospitalsystem.

The storm, hitting thecity during the evening rush hour, crumbled cars and tractor-trailers along amajor interstate highway and caused havoc, a local TV channel ABC13 reported.

Hail and heavy rainswept the metro area and emergency workers even had trouble responding to"widespread" reports of injuries, according to reports.

Flash flooding andtornadoes also killed three people in Arkansaslate Thursday and early Friday. Three others were reported missing in floods.

The U.S. averagesmore than 1,200 tornadoes a year. Most tornadoes in the country are relativelysmall. Of the 60 top-of-the-scale EF-5 tornadoes to hit since 1950, Oklahoma and Alabamahave been hit the most -- seven times each, according to media reports.

A tornado, classified asan EF-5, hit Moore, in the southern part of the Oklahoma Citymetropolitan area, on May 20, killing 24 people and injuring 377 others. Asmany as 12,000 homes were damaged.