Egypt's miltary ruler said Tuesday he is prepared to hold a referendum on transferring power to a civilian government immediately, following a massive demonstration in Cairo's Tahrir Square that saw tens of thousands turn out to demand regime change.

Field Marshal Hussein Tantawi said they would hold the plebiscite if the people demanded it. But protesters responded with chants of "leave, leave" now.

The pledge comes after the ruling military council initially offered to transfer power to a civilian government by July of next year.

Abu al-alla Madi and Mohammed Selim el-Awa, two politicians who attended a five-hour crisis meeting with the military rulers, said Tuesday that the council also accepted the resignation of Prime Minister Essam Sharaf's government and will form a "national salvation" cabinet to replace it.

The move seems designed to placate widespread rage that has wracked the country for four days and resulted in the deaths of at least 29 people and more than 1,700 injured.

Previously, the military rulers had floated late next year or early 2013 as the timetable for transferring power. The council also agreed to hold presidential elections before the end of June 2012, a vote the ruling council has deemed the final stage necessary for transferring power.

Activists called for a "million-man march" on Tuesday, hoping to increase the number of protesters in the Tahrir Square, which was the epicentre of the revolt that ousted Hosni Mubarak in mid-February.

Many have been calling for a "second revolution."

Security forces have largely stayed out of the square since Monday. 

CBC's Derek Stoffel reported isolated clashes in and around Tahrir Square, with young men throwing rocks and pieces of concrete while security forces fired rubber bullets and tear gas.

"Protesters say they will do whatever it takes to keep the security forces out of the square," Stoffel reported from Cairo on Tuesday.

Elections scheduled next week

Tens of thousands of protesters are already in the square and many more are on the way, some being bused in from other areas.

The two sides have been engaged in intense clashes since the unrest began on Saturday, with protesters trying to force out the generals who have failed to stabilize the country, salvage the economy or bring democracy more than nine months after taking the reins from Mubarak.

In many ways, the protests bear a striking resemblance to the 18-day uprising beginning Jan. 25 that toppled Mubarak. The chants are identical, except that military ruler Tantawi's name has replaced Mubarak's.

"The biggest mistake was leaving the square [the first time]," one protester told CBC News.

Although the government has said it is committed to upcoming parliamentary elections — scheduled for Nov. 28 and something the council reiterated on Tuesday— some commentators have cast doubt on such plans given the widespread unrest.

CBC's Sasa Petricic said many Egyptians are confused about what will happen after the elections, particularly as the country moves towards drafting a new constitution.

"Before [a transfer of power] the military still has final say on everything that happens and one of the main concerns has been that they set the rules for the election, they set the rules for the drafting of a new constitution and they have so far tried to carve themselves out very special powers within that constitution," he said from Egypt.

That is extremely worrying for Egyptians because they don't trust the military, Petricic said.

"All of that undermines the basic ideas, the basic principles these people have been sitting out in the square for," he said. 

12,000 tried in military courts

Amnesty International, meanwhile, harshly criticized the military rulers in a new report.

The London-based group documented steps by the military that have fallen short of increasing human rights and, in some cases, have made matters worse than under Mubarak.

The report called for repeal of the Mubarak-era "emergency laws," and said the army has placed arbitrary restrictions on media and other outlets.

Egyptian security forces have continued to use torture against demonstrators, the report said, and some 12,000 civilians have been tried in military trials, which it called "unfair."

Meanwhile, Egypt's benchmark stock index plunged on Tuesday, with a temporary suspension of trading failing to cool selling by investors panicked by escalating violence and protests in Cairo. . The EGX30 index closed 4.78 per cent lower, continuing its slide after trading was suspended for nearly an hour on the Egyptian Exchange after the broader EGX100 index fell by over 5.4 per cent.

The Tuesday losses marked the 10th consecutive trading session in which the market declined.

With files from The Associated Press