OKLAHOMA CITY - At least two rollover crashes on metro thoroughfares caused major traffic delays, Thursday afternoon.

First responders were initially called out to a single-vehicle rollover crash on the northbound side of Interstate 35 in NE OKC.

Authorities had to shut down two of the inside lanes of NB I-35, just to the north of NE 50th St., due to the crash. The number of injuries and their severity is not known at this time. Traffic is backed up for about a mile in both directions while crews work the scene. 

Shortly after the first crash, crews were called out to the scene of a second rollover wreck involving a single bobtail pickup, this one on the westbound side of Interstate 40, just to the east of the Dallas Junction of I-35. The driver of the pickup was not injured.

The causes for either crash have not yet been determined.

Keep checking with News 9 and News9.com for more information.