Egypt's army has vowed it will not use force against the tens of thousands of people protesting for the removal of the regime of President Hosni Mubarak.
It said it respected the "legitimate rights of the people".
The statement comes ahead of a massive march planned for Cairo on Tuesday and amid a call for a general strike.
Meanwhile, new Vice President Omar Suleiman said Mr Mubarak had asked him to open dialogue with all political parties on constitutional reform.
Earlier, Mr Mubarak announced a cabinet reshuffle to try to head off the protests, replacing the widely despised Interior Minister Habib al-Adly.
Defying the curfew
In its statement, carried on Egyptian media, the military said: "To the great people of Egypt, your armed forces, acknowledging the legitimate rights of the people... have not and will not use force against the Egyptian people."
BBC Middle East editor Jeremy Bowen says the announcement is absolutely critical because it takes away a huge measure of uncertainty from the mind of any potential demonstrator.
And the BBC's Lyse Doucet, in the Egyptian capital, says people will see similarities to what happened in Tunisia, when the army's refusal to fire on protesters led to the ousting of President Zine al-Abidine Ben Ali after 23 years in power.
She says the language will appeal to the thousands of people in Cairo's central Tahrir (Liberation) Square, where there has been a very friendly atmosphere between protesters and soldiers. They are trying to defuse any tension before the mass demonstrations planned on Tuesday.
The opposition has called for a million people to take to the streets of Cairo.
A similar mass march has been called for Alexandria.
Train services in Egypt have been halted between the curfew hours of 1500 and 0800 (1300 and 0600 GMT) and EgyptAir said it was cancelling all domestic and international flights between these hours, a move correspondents say may be intended to restrict attendance at demonstrations.
However, thousands of protesters are still camped out in Tahrir Square, defying the curfew.
Leaflets were being distributed to the crowds calling on the army to take the people's side and resist orders to move against them.
The AFP news agency reports that internet service provider, the Noor Group, went down on Monday - removing the country's last remaining connection.
In his statement, Mr Suleiman said the president had ordered new government policy to be outlined "in the next few days".
"It will include clear and definite policies to carry out his pledges within an expedited time frame in a way that would restore the trust in the Egyptian economy... and promptly deal with the priorities of tackling unemployment, fighting poverty and corruption and achieving the required balance between wages and prices."
Mr Suleiman also said that new elections would be held in some districts where there was evidence of irregularities in last November's parliamentary poll, in which Mr Mubarak's party won 83% of seats.
The statement follows increasing international pressure. The US state department has despatched a special envoy to Cairo, former ambassador to Egypt Frank Wisner, to urge Egyptian leaders to embrace political change.
Earlier Mr Mubarak's reshuffle made few major changes, with Foreign Minister Ahmed Aboul Gheit and Defence Minister Gen Mohamed Hussein Tantawi - who also becomes deputy PM - both keeping their posts.
Interior Minister Adly was replaced by Mahmud Wagdi, an army general.
The line-up confirms a purging of those behind Egypt's economic liberalisation and growth over the past few years, analysts say, and a move towards a more military cabinet.
A number of businessmen holding economic posts have been removed. Some Egyptians have resented the influence of the tycoons.
Concerns are growing about the economy after a week of protests. World oil prices on Monday topped $100 (£62) a barrel amid fears of the ongoing unrest.
Few of the 50,000 protesters in Tahrir Square appeared appeased by the cabinet changes.
"We will stay until the coward leaves," the crowd chanted.
One demonstrator told the BBC: "This is not a new government. This is the same regime - this is the same bluff. [President Mubarak] has been bluffing us for 30 years."
Amid the protesters' call for a general strike, banks, schools, many businesses and the stock market were closed for a second day, with queues forming outside food stores.
Some police are back in parts of Cairo, having abandoned their posts on Friday.
Thousands of people also rallied in Alexandria, and there were sizeable demonstrations in Mansoura, Damanhour and Suez.
Israel has agreed to allow Egypt to deploy 800 more troops to the Sinai, the first such deployment since the 1979 peace deal between the two nations. The troops will ring the Red Sea resort of Sharm el-Sheikh.
Israeli PM Benjamin Netanyahu warned against the takeover of Egypt by "an organised Islamic group" as had happened in Iran.
The death toll from the protests so far is hard to assess but is thought to be at least 100. Human Rights Watch in Cairo told the BBC World Service its collation of deaths put the toll at 174.
Many countries are evacuating citizens, leading to chaotic scenes at Cairo airport as air traffic becomes congested and flights are cancelled or delayed.