Egypt's President Hosni Mubarak is to make an address on national television shortly, amid suggestions that he is preparing to step down.
The al-Arabiya TV network is reporting that he will transfer his powers to his deputy, Vice-President Omar Suleiman.
The country's military, meanwhile, has said it will "support the legitimate demands of the people".
It comes on the 17th day of protests against Mr Mubarak's 30-year rule.
Thousands of demonstrators have gathered in Cairo's Tahrir Square, waving flags and chanting slogans as they await what they hope will be President Mubarak's resignation.
The euphoric atmosphere spread after an Egyptian army commander told protesters that all their demands would be met, but some are expressing concern that the military could try to seize power.
Doctors, bus drivers, lawyers and textile workers were on strike in Cairo on Thursday, with trade unions reporting walkouts and protests across the country.
State TV has shown pictures of Mr Mubarak in his office, holding talks with Vice-President Suleiman.
State news agency Mena says the high council of the armed forces, meeting without Mr Mubarak, is in a state of continuous session "to protect the nation, its gains and the aspirations of the people".
Essam al-Erian, a senior member of the Muslim Brotherhood, Egypt's biggest opposition group, said he feared that the Egyptian military was staging a coup.
"It looks like a military coup... I feel worry and anxiety," he told Reuters news agency. "The problem is not with the president, it is with the regime."
The director of the US Central Intelligence Agency (CIA), Leon Panetta, said he had received unconfirmed reports that Mr Mubarak would step down on Thursday evening.
"I've received reports that, possibly, Mubarak might do that," he told a congressional intelligence hearing. "We have not gotten specific word that he, in fact, will do that."
President Barack Obama, addressing students in Michigan, said: "What is absolutely clear is we are witnessing history unfold. It's a moment of transformation."
Mr Mubarak had previously pledged to quit office after presidential elections due to be held in September.
Negotiations between the government and opposition groups have made little progress, with protesters disillusioned by plans for reform put forward by Mr Mubarak's government.
In recent days, the US government had stepped up its call for the protesters' concerns to be addressed.