April 6 Youth Movement, which helped launch Egypt's 2011 uprising, has lashed out at fresh "trumped up" accusations of treason after leaked phone calls by senior members Ahmed Maher and Mohamed Adel were aired on TV.
The leak came just hours after the pair were jailed for organising an unlicensed protest.
Privately owned TV channel Al-Kahera Wal Nas (Cairo and the People) on Sunday broadcast phone calls of Maher and Adel that it said proved the movement serves a foreign agenda.
In one of the calls, the men mentioned rumours about Maher receiving $500,000 plus another fund from the wife of the emir of Qatar, Sheikha Moza – allegations he mocked during the conversation.
The activists also touched upon "training in Serbia," communication with the International Republican Institute (IRI), and the willingness of the European Union and the Danish embassy to fund the group.
In a statement on Monday, April 6 condemned "intelligence-directed" media outlets for spreading "fabrications" by the state security apparatus.
A number of Egyptian political groups and activists have received training and financing from international NGOs and human rights organisations, such as IRI, Freedom House, and the National Democratic Institute. This has been interpreted by the authorities and critics as conspiring with foreign states.
"Whoever has evidence of treason, spying or funding regarding April 6, go and submit it to the glorious judiciary… Or is defamation the objective?" the group added.
A court on Sunday sentenced April 6 founder Ahmed Maher, prominent member Mohamed Adel, and long-time activist Ahmed Douma, to three years in prison for organising an unauthorised protest last month and assaulting members of the security forces. They were also fined LE50,000 each.
The men were found guilty of violating a controversial law enacted last month that requires police authorisation for demonstrations. It was the first conviction for protesting without permission under the new legislation.
Their arrests were ordered after Maher's supporters allegedly clashed with police outside a Cairo court on 30 November, when Maher was handing himself in for questioning over allegations he had organised a separate illegal protest in defiance of the new law.
"It's unreasonable that we have been accused of spying and treason for six years, and when we get caught, it is over charges of protesting that we have never denied," the group added.
A number of secular activists have been arrested in recent weeks for violating the new law which rights groups say is designed to curb protests.
The case has fuelled fears of an expanding crackdown on public dissent by the country's interim authorities, beyond a sustained campaign on Islamists since the army's ouster in July of president Mohamed Morsi amid massive protests. Hundreds were killed and thousands arrested, including the top leadership of Morsi's Muslim Brotherhood movement.
Morsi himself is standing trial in three separate cases over charges including the murder of opposition protesters and a prison break.