April 6 Youth Movement co-founder Ahmed Maher has criticised a "smear" campaign against Mohammed ElBaradei following his condemnation of a crackdown on the Muslim Brotherhood.
Speaking via Twitter on Sunday, Maher said: "New fascists attack and accuse those who even partially disagree with them of treason. ElBaradei is a symbol of January 25  and June 30 ."
"A particular form of fascism is gone and another has replaced it," Maher added.
ElBaradei, who resigned as interim vice president after security forces killed hundreds of Mohamed Morsi supporters at protest camps in Cairo and Giza on 14 August, criticised on Sunday a "fascist media campaign" that "does not value human life."
"Violence only begets violence,” the former liberal Constitution Party leader added in comments via Twitter.
The Nobel peace laureate has been criticised by journalists and politicians who claim his resignation from the interim government was "unpatriotic" and accuse him of abandoning the government at a critical moment.
Ahmed Maher and April 6, who played a key role in preparing for the January 25 uprising against Hosni Mubarak, have also been the target of intense scrutiny and attacks by opponents.
The movement is labelled a "Muslim Brotherhood sleeping cell" by opponents in the media due to it's criticism of the current government.
April 6 condemned the violent dispersal of pro-Morsi camps in August which left hundreds dead, saying: "Not only is Egyptian blood cheap despite the great January  revolution, it is now going for free."
Opponents of April 6 also highlight the movement's decision to back Mohamed Morsi in the presidential runoff in June 2012.
April 6, as well as some opposition parties and national figures, supported Morsi's bid for the presidency to prevent Mubarak-era prime minister Ahmed Shafiq from capturing the post.
Shortly after Morsi's election, April 6 joined the ranks of the opposition, charging him with betraying the goals of the January 25 Revolution.
The youth movement also supported Tamarod's 30 June demonstrations to force early presidential elections.
Following the ouster of Morsi in July, April 6 condemned "church burnings, terrorism and the killing of soldiers in Sinai" - crimes attributed to the Muslim Brotherhood.