Police said, the labourers held a protest demonstration and blocked the Delhi-Ludhiana-Jalandhar National highway setting two cars and two tempos on fire on Thursday night, Dec 3.
The migrants stoned a bus coming from Delhi injuring two passengers at Dhandari on Friday morning, Dec 4.
A car was also stoned, but the driver managed to speed away from the spot, police added.
"Since the protestors were in large numbers we had to fire around 10 rounds in the air to disperse the labourers," SSP Sukhchain Singh Gill said, adding reinforcements have been rushed to the spot.
The labourers are protesting against the failure of the police to register cases in connection with three incidents of snatching of cash from three labourers who had received their wages during the week.