Samajwadi Party chief Akhilesh Yadav accused the ruling Bharatiya Janata Party (BJP) in UP of using 'fake encounters' to divert attention from 'real issues'.
Yadav, a former UP chief minister, tweeted shortly after state police confirmed the killing of Asad Ahmad - the son of "gangster-politician" Atiq Ahmad - in an encounter in Jhansi district.
"The (government) does not have the right to decide what is right or wrong," he said.
Asad Ahmad's killing comes less than a month before UP civic body polls.
Asad and another accused in the same case - Ghulam - were shot dead in Jhansi and police recovered two foreign-made weapons.