They were attacked with sticks by saffron-clad men, the video of which has gone viral. The locals, however, rushed to their rescue and informed the police.
"We have lodged an FIR in this connection at Hasanganj police station against unidentified persons immediately after the matter came to our notice," a police official said.
The main accused, identified as Bajranj Sonkar, has been arrested, he said. Sonkar claims to be the president of the Vishwa Hindu Dal.
Incidents of harassment of Kashmiris, especially students, have been reported from various parts of the country after the Pulwama terror attack on February 14.
Following the incident, former Jammu and Kashmir Chief Minister Mehbooba Mufti said "You humiliate & assault Kashmiris. Make them feel like criminals & that they dont belong to this country. Why are you surprised then when young pliable men are taken under the wings of terror groups & indoctrinated?".
Even Former Jammu and Kashmir Chief Minister Omar Abdullah on Thursday condemned the thrashing of Kashmiri vendors in Lucknow. "Nothing will do more damage to the idea of India in Jammu and Kashmir than videos like these," he said in a series of tweets along with the video post.
"Keep thrashing Kashmiris like this on the streets at the hands of RSS/Bajrang Dal goons and then try to sell the idea of 'atoot ang' (unbreakable part), it simply won't fly."
He also called upon Union Home Minister Rajnath Singh to punish "those guilty of this assault". Singh represents the Lucknow parliamentary constituency.