Sources said that Rahul Gandhi told the National Human Rights Commission (NHRC) officials that "it was not an issue of individual cases but an attack on the very idea of India, wherein police used much brute force against civil".
A party insider said that an inquiry should be initiated against the officials concerned as their conduct was against the law and the very ethos of policing.
Rahul later tweeted: "A delegation of Congress leaders presented the NHRC with evidence of atrocities against citizens of Uttar Pradesh by the state government, which has gone to war against its own people. The NHRC must act decisively to protect the idea of India and the constitutional rights of our citizens."
Party spokesperson Abhishek Singhvi said that the commission had been given evidence about police brutality in the form of audio and video clippings on how the victims were shot in the stomach and chest.
"Photographs have also been given; there were 23 deaths but no FIR has been registered against the police," he said.
Priyanka Gandhi had visited many victims and their families in western Uttar Pradesh, which was the worst hit by violence which broke out in December last year.
She visited Bijnor, Muzaffarnagar, Meerut and Lucknow to meet those at the receiving end of the violence and sat on a dharna at India Gate here to express solidarity with the protesters. The party also held a symbolic protest at Rajghat.
At least two dozen persons were killed in alleged police firing in Bijnor, Meerut, Kanpur, Firozabad and other places.
( With inputs from IANS )