Bajrang Dal activists allegedly thrashed four people near Jiroli village on the outskirts of Lucknow on the suspicion of them being "cow thieves".
The incident occurred when gau rakshaks, led by Bajrang Dal district president Kedar Singh, tried to intercept a matador carrying a buffalo. The driver refused to stop, police said.
The activists raised an alarm and a road block was laid by other members of the group at a short distance ahead. Seeing the road block, the four persons who were in the matador jumped out and tried to escape, they added. However, they were nabbed and beaten up by the crowd which had gathered at the spot before being handed over to the police along with their vehicle.
The Bajrang Dal activists alleged that the behaviour of the four persons had been "suspicious" and accused them of being cattle thieves.
According to police, the four apprehended persons are being interrogated.
The incident came as the Home Ministry issued an advisory asking all states not to tolerate anyone taking law into their hands in the name of protecting cow and take prompt action against such offenders. The advisory came two days after the Prime Minister Narendra Modi denounced cow vigilantes and asked people to beware of its 'fake' protectors trying to divide society and the country and asked the states to severely punish them.