Egypt unrest: Protesters gather for Tahrir Square rally
Egyptians are gathering in Cairo's Tahrir Square for a mass protest to put pressure on the military to speed up the transfer of power.
Violence broke out again in streets close to the square and a BBC correspondent there describes the situation as volatile.
Three days of clashes between security forces and protesters have left at least 28 dead and hundreds wounded.
The unrest has thrown into doubt elections due to be held next week.
The elections are due to set in train a process of transition to democracy following the toppling of President Hosni Mubarak in February.
Demonstrators are concerned that the military intends to hold on to power, whatever the outcome of the vote.
The military leadership, the Supreme Council of the Armed Forces (Scaf), is holding talks with political leaders - a day after the military-appointed civilian cabinet offered its resignation.
It is not clear if the resignation has been accepted.
Later on Tuesday, Abou Elela Mady, head of the Wasat Party, was quoted by Al-Jazeera as saying that the military had agreed to a presidential election before July - a key demand of the protesters.
Prime Minister Essam Sharaf, appearing briefly outside the cabinet's headquarters in Cairo on Tuesday, pleaded for calm.
"All I ask of the people is that they leave, calm down. We have responded to what they wanted. We were so close to our main goal which is the elections. This is what is important, the political shift," he said.
The Muslim Brotherhood - whose Freedom and Equality party is widely seen as the most formidable contender in the elections - is also taking part in the talks.
However, it has refused to participate in Tuesday's protest - presumably, say correspondents, because it wants the election to go ahead to show how much support it has in the country.
Field Marshal Mohamed Hussein Tantawi, the head of Scaf, is expected to make a statement later, Egyptian television reports.
Tear gas and bullets
Thousands of protesters have been streaming into Tahrir Square, joining the hundreds that camped there overnight.
The BBC's Wyre Davies, in the square, says the scene is noisy and chaotic.
There has been more violence, much of it again in the streets leading between the square and the interior ministry building, he says.
One protester near the ministry was seen hanging an effigy of Field Marshal Tantawi from a traffic light.
The square and surrounding streets have been the scene of running battles between protesters and security forces in recent days.
There has been violence in other parts of Egypt too. Two people died in the port city of Ismailia on the Suez Canal after security forces clashed with some 4,000 demonstrators, witnesses said.
The military council has expressed its "deep regret" for the victims of the violence and has asked the justice ministry to open an investigation.
The clashes began on Saturday following demonstrations against proposed constitutional changes unveiled by the interim government.
A draft document setting out principles for a new constitution proposed that the military and its budget could be exempted from civilian oversight.
Parliamentary elections are due to begin on 28 November and be staggered over three months.
The military's timetable calls for the new parliament to then choose a 100-member constituent assembly to draw up a new constitution within six months.
A referendum must then approve the document before a presidential election is held. That would mean the military still in power until late 2012 or early 2013.
Protesters, however, want the presidential vote to take place after parliamentary elections.
In a report published on Tuesday, Amnesty International said Egypt's military rulers had "completely failed to live up their promises to Egyptians to improve human rights".
Amnesty said the military council had carried on many of the abusive tactics of the Mubarak era, including torture of suspects, targeting critics and banning critical media.
"The euphoria of the uprising has been replaced by fears that one repressive rule has simply been replaced with another," Amnesty said.