AUSTIN (KXAN) -- Lanes reopened Thursday after they were shut down on Interstate 35 near Round Rock due to "law enforcement activity," the Texas Department of Transportation said on social media. TxDOT said around 6 p.m. that the northbound and southbound lanes on I-35 and State Highway 45 North Toll were all closed. Then, shortly before 10 p.m., the agency said the lanes reopened. All lanes were shut down on Interstate 35 near Round Rock after reported law enforcement activity (KXAN viewer photo)All lanes were shut down on Interstate 35 near Round Rock after reported law enforcement activity (KXAN viewer photo) It was not immediately clear what led to the law enforcement activity on I-35. No other details were available Thursday.