Protesters are trickling in to Cairo's Tahrir Square, the planned starting point of a "march of a million", on the eighth day of an uprising that has claimed at least 125 lives in clashes between demonstrators and police.
Another million-strong march is planned in the Mediterranean port city of Alexandria, as national train services were cancelled in an apparent bid to stymie protests.
In Cairo, number of people gathered in Tahrir Square on Tuesday morning was larger than had been seen on earlier days at the same time.
The new protests will come as the police have returned to the streets.
But while the police's posture to be adopted in the face of the strike and marches remains unknown, the Egyptian army stated clearly on Monday that it would not stop them.
Faced with the prospect of massive numbers trying to converge on the capital, Egyptian authorities stopped all train traffic with immediate effect on Monday afternoon.
And state-owned national carrier EgyptAir said it was cancelling all domestic and international flights from 3 pm (1300 GMT) to 8 am (0600 GMT) until further notice, coinciding with a curfew in Cairo, Alexandria and Suez.
Army Holds Back
In a statement on Monday the army said "freedom of expression" was guaranteed to all citizens using peaceful means. "To the great people of Egypt, your armed forces, acknowledging the legitimate rights of the people," stress that "they have not and will not use force against the Egyptian people," said the statement.
It was the first such explicit confirmation by the army that it would not fire at demonstrators who have taken to the streets of Egypt and comes a day before Tuesday's "march of millions".
"The presence of the army in the streets is for your sake and to ensure your safety and well-being. The armed forces will not resort to use of force against our great people.
"Your armed forces, who are aware of the legitimacy of your demands and are keen to assume their responsibility in protecting the nation and the citizens, affirms that freedom of expression through peaceful means is guaranteed to everybody." the army statement said.
It urged people not to resort to acts of sabotage that violate security and destroy public and private property. It warned that it would not allow outlaws to loot, attack and "terrorise citizens".
Protesters have called for a massive demonstration and a rolling general strike on Tuesday.
The so-called April 6 Movement said it plans to have more than one million people on the streets of the capital Cairo.
The call came as Mubarak swore in a new cabinet in an attempt to defuse ongoing demonstrations across the country.
Call for talks
Omar Suleiman, Egypt's new vice president, said on Monday that Mubarak had tasked him with opening "immediate" dialogue with the opposition "around all the issues concerning constitutional and legislative reforms".
He said steps were underway to implement decisions of the appeals court contesting results of autumn legislative elections in certain constituencies.
However, members of the opposition in the Egyptian capital reject the offer of dialogue.
