A large storm cell, which reportedly produced a multiple vortex tornado, passes south of El Reno, Oklahoma, May 31, 2013. The National Weather Service issued a tornado emergency for parts of Oklahoma on Friday, describing weather conditions as "particularly dangerous" a day after more than a dozen reported twisters ripped through the region. [Photo/Agencies]

OKLAHOMA CITY, Okla - Violent thunderstorms spawned tornadoes that menaced Oklahoma City and its already hard-hit suburb of Moore on Friday, killing a mother and her baby, and officials worried that drivers stuck on freeways could be trapped in the path of dangerous twisters.

The mother and her baby were killed while traveling on Interstate 40, just west of Oklahoma City, when their vehicle was picked up by the storm, said Betsy Randolph, spokeswoman for the Oklahoma Highway Patrol. The interstate was shut down due to the storm, with multiple crashes and injuries.

National Weather Service meteorologists at one point declared a tornado emergency for parts of the Oklahoma City metropolitan area, including Moore, and storm spotters were tracking a tornado in the western suburb of Yukon.

One twister touched down on Interstate 40 and was headed toward Oklahoma City. A tornado also touched down in Moore, which was hit by a massive EF-5 twister last week that killed 24 people.

"The Interstate is at a standstill," Randolph said. "We are begging people to get off the Interstate and seek immediate shelter ... We are in a dire situation."

Oklahoma Governor Mary Fallin told CNN that motorists stuck on any freeway in the path of a twister should try to go in the opposite direction to where the twister was coming from.

"What we saw from the tornadoes that came through Moore and the other ones last week was that people who were in cars on the Interstate were killed," Fallin told CNN.

Moore Mayor Glenn Lewis told CNN it was "unbelievable" that Moore had been hit again.

Tim Oram, meteorologist for the National Weather Service, said it was difficult to know exactly how many tornadoes had touched down, but three major storms were potentially producing tornadoes throughout the center of the state.