Tornadoes slammed Oklahoma City and its suburbs Friday, killing at least nine and injuring dozens of others, according to the National Weather Service office in Norman, Okla.

Deadly twisters swarmed the city and Interstate 40, which was shut down after the storm trapped people in vehicles, uprooted trees and power lines, and scattered debris in all directions.

Two of the deaths occurred in Union City and one was in El Reno, west of Oklahoma City, Reuters reported, citing Amy Elliott, a spokeswoman for the state's Office of the Chief Medical Examiner.

A mother and a baby were killed when their vehicle was lifted off I-40 by the storm, according to the Associated Press, citing Betsy Randolph, a Oklahoma Highway Patrol trooper.

About 50 people -- including five who are stated to be in critical condition -- were being treated for storm-related injuries, according to the Integris Health hospital system.

"For reasons that are not clear to me, more people took to the roads, more than we expected. Everyone acted differently in this storm, and as a result, it created an extremely dangerous situation," Oklahoma City Mayor Mick Cornett was quoted as saying by Reuters.

However, he said that Friday‚Äôs storm did not appear as powerful as the one that devastated the suburb of Moore last week and killed 24 people. A tornado also touched down in Moore on Friday.

National Weather Service meteorologists had earlier issued tornado watches over large areas of Oklahoma, and severe storm warnings for counties in Illinois and Missouri, where dangerous conditions are expected to continue until Saturday.

Meteorologists for the weather service said that it is difficult to know how many tornadoes had hit, but confirmed that three major storms were potentially responsible for the tornadoes that affected the state, according to the Reuters report.