The Biden campaign canceled a planned event in Central Texas after being harassed by Trump supporters on Friday, according to the Texas Democratic Party.

Videos started going viral on Saturday of a group of trucks and SUVs flying Trump flags surrounding a Biden campaign bus on the highway. The Trump trucks had been camping out the shoulder of the road, apparently waiting for the Biden bus. A Biden campaign spokesperson told Forbes that the vehicles “attempted to slow the bus down and run it off the road,” on Interstate 35.

Neither Biden nor Kamala Harris was on the bus. Texas liberal icon Wendy Davis, who is running for Congress, was on board, Texas Democrats told Forbes.