Sherif Shawky, spokesman of Egyptian Prime Minister Hazem Beblawi, has said on Egypt state television that the Muslim Brotherhood is a terrorist organisation.
"Prime Minister Beblawi has declared the Muslim Brotherhood as a terrorist organisation," the premier's spokesman Sherif Showky said on state television on Tuesday morning.
Al Jazeera's producer, Mohamed Fahmy reporting from Cairo, said Shawky's remarks have not been confirmed by the minister.
However, a cabinet meeting was to be held later on Tuesday at which an official decision was expected to be made about the movement's status in the country.
The expected declaration came as more than 450 jailed Muslim Brotherhood members reportedly launched a hunger strike over their "inhuman treatment" after being jailed following the military's overthrow of president Mohamed Morsi.
A Twitter account operated by the Brotherhood, which has largely been driven underground by a massive crackdown, said prisoners have been "banned from family visits, legal counselling, medical care and (live in) overcrowded and unhygienic cells."
Security forces have arrested thousands of Brotherhood members, including virtually the entire top leadership, since Morsi was deposed on July 3.
The Brotherhood said several senior figures were taking part in the strike, including wealthy financier and onetime presidential hopeful Khairat al-Shater, senior official Essam al-Erian, former legislator Mohamed Beltagi and Essam al Haddad, an advisor to Morsi during his presidency.
It did not say whether Morsi himself or Brotherhood Supreme Guide Mohammed Badie were also doing so.
|Anger over sentencing Egypt's three activists
Human Rights Watch said this month that Egypt's military-installed authorities had detained five Morsi aides for nearly five months without disclosing their whereabouts, saying it amounted to an "enforced disappearance."
Three of them, including Haddad, have been recently moved to Tora prison where Badie is held.
Murad Ali, spokesman of the Freedom and Justice Party, the political wing of the Brotherhood, said the movement's members were held in solitary confinement in prisons. He is being held in Tora prison.
"Even when we go out of the cells for two hours a day, each prisoner is let out alone," Ali said in a written statement passed through an intermediary.
"They are isolating us from everything."
Ali said the authorities were not allowing the movement's members to read newspapers and had confiscated their books and radios.
A crackdown launched by Egypt's interim rulers targeting the supporters of Morsi has left more than 1,000 people killed in street clashes since he was deposed.