Om Vir Singh 'Fauji', a retired army man who was the vice-president of BJP unit in Mirapur town, was out for a morning walk when two assailants fired multiple shots at him with country-made pistols at around 7 AM at Monty crossroad, police officials said.
47-year-old Singh, who had a licensed revolver with him, too fired at the attackers but they snatched it from him.
The criminals shot Singh with his own revolver before fleeing with the weapon, they said.
The body has been sent for post mortem.
Following the incident, Singh's family members and BJP workers staged protests and blocked a road. Senior police officials, who reached the spot, assured the protesters of speedy investigation in the case.
The incident occurred even as Chief Minister Akhilesh Yadav was holding a meeting in Lucknow with top police and other officials to review the law and order situation after the Samajwadi Party government came under flak over the Badaun gangrape incident and the killing of BJP leader Vijay Pandit in Dadri in Greater Noida on Saturday.
Pandit's family had alleged political vendetta and pointed fingers at a Samajwadi Party leader, who had denied the allegation.
BJP, however, termed the meeting as a farce and said that it would have been better if the CM would have held a review of his own party organisation, whose workers were "biggest challenge for law and order".
State BJP spokesman Vijay Bahadur Pathak said that the day the government was claiming improved law and order situation, the criminals demonstrated their brutal power by killing Singh in Muzaffarnagar.
Demanding immediate arrest of Singh's killers, he alleged, "The phase of political killings has started in UP, which is dangerous".
Security personnel have been deployed as tension prevailed in the area after the killing.
Muzaffarnagar, which lies in western Uttar Pradesh, is a sensitive district and had witnessed communal violence in September last year that has left over 60 people dead.
The recent Lok Sabha elections saw BJP winning 71 out of the 80 seats in the politically crucial state while Samajwadi party suffered a rout.
Congress said it unequivocally condemns such deplorable incidents as it believes that violence is the "anti-thesis to democracy".
Party spokesperson Abhishek Singhvi at the same time said that there was "no point in politicising" the matter even as it made it clear that it has time and again stressed that the Uttar Pradesh government has to considerably improve law and order and governance.
"We do not want to make it sensational and politicise it," he said adding that talks like demand for President's Rule is nothing but "politicizing the issue".
Referring to the incident, former Home Secretary and BJP leader RK Singh said, "I had said 2-3 days ago said that in my assessment law and order in UP has broken down and I stand by my assessment."
Condemning the murder of Om Vir Singh 'Fauji', local BJP leader Pradhumna Sharma said, "We appeal to the Chief Minister that the accused must be arrested as soon as possible."
Meanwhile, Rakesh Jolly, SP (crime) said that the assailants were hiding and attacked Singh from behind.
"Exchange of fire took place and they snatched his revolver and shot him," he said.
The SP said they had no information that Singh was a BJP office bearer.