The Maoists demanded an independent probe into the circumstances leading to the killing of Kishenji in Burisole forest in West Midnapore district yesterday.
A call for a two-day bandh in West Bengal from November 26 was also given by Maoists in protest against the alleged fake encounter.
"Kishenji was killed in a fake encounter. To protest this we are calling a two-day statewide bandh from November 26 and a week-long protest," Maoist state committee member and spokesperson Akash told PTI on phone from an undisclosed location.
Rejecting the allegation, CRPF Director-General Vijay Kumar said Kishenji was killed in a 'very clean and successful' operation by the joint forces in West Midnapore district.
"It was a very clean and successful operation and our boys did not waste a minute," Kumar told reporters in Burisole forest in Jhargram area where Kishenji was killed.
"No, no, no" he said when asked about the allegation that Kishenji was eliminated in a fake encounter.
Telugu poet and Maoist sympathiser Varvara Rao also alleged that Kishenji had been killed in a fake encounter.
"Kishenji was arrested two days ago and kept in police custody. He was killed in a fake encounter. It is a murder case which should be probed,'' Varvarao Rao told reporters at Kolkata airport.
Rao had also said that the "story" of an encounter was a fabrication.
Maoist spokesperson Akash when asked to substantiate his allegation said, "He was arrested when our people were present nearby and then murdered in cold blood. We demand an independent investigation into the killing of our leader".
CPI leader Gurudas Dasgupta in a letter to Home Minister P Chidambaram said, "The story of the encounter appears to be fake, needs to be inquired into and the government must clarify".
Questioning the manner in which Kishenji was killed, Dasgupta asked government to clarify whether he was done to death in "cold blood" after being arrested.
Dasgupta, who spoke to Chidambaram on phone, quoted a "source" to say that Kishanji was arrested at noon yesterday and "subsequently killed in a cold-blooded murder".
"If my information is right, then it is an act of dastardly crime in violation of all national as well as international laws," he said in the letter.
Human rights activist and the head of government- appointed interlocutors, Sujato Bhadra also demanded an inquiry into Kishenji's killing.
Samajwadi Party also levelled the allegation of a fake encounter and said Naxalism cannot end through "massacre" of Naxal leaders.
"The way reports of Kishenji's killings have come out, it does not look like Kishenji was killed in an encounter... It is a fake encounter," Samajwadi Party leader Mohan Singh told reporters in New Delhi.
In Bihar, the CPI(M-L) Liberation urged West Bengal Chief Minister Mamata Banerjee to order a judicial inquiry into the killing of Kishenji, just as she had demanded one for the death of rebel leader Azad in Andhra Pradesh last year.
"There is a similarity in the encounter deaths of Azad and Kishenji. Mamata Banerjee should order a judicial inquiry into the killing of Kishenji," CPI (M-L) leaders Raj Kumar Singh and Krishna Adhikari told reporters in Patna.