Clashes have again erupted in the Egyptian capital as security forces continue their efforts to clear Cairo's Tahrir Square of protesters. The health ministry confirmed the death toll from violence on Sunday and into Monday had risen from 11 to 20.
Two people died when the assault began on Saturday, and 1,750 have been injured since the violence started.
This is the longest continuous protest since President Hosni Mubarak was ousted in February, and it casts a shadow over elections due to start next week.
Demonstrators, mostly drawn from Islamic groups, say they fear Egypt's governing Supreme Council of the Armed Forces is trying to retain its grip on power.
In recent weeks, protesters - mostly Islamists - have been holding demonstrations against a draft constitution. Liberal elements claim that they have been intimidated by Islamic extremists when they attempted to join the demonstration. The protesters claim the proposed constitution would allow the military to retain too much power after a new civilian government is elected.
Earlier this month, the military council produced a draft document setting out principles for a new constitution, under which the military and its budget could be exempted from civilian oversight.
The military also want rules to protect individual and minority rights as a defence against Islamic extremism.
The announcement provoked a furious reaction from the Muslim Brotherhood. Analysts suggest that Islamists could win 40 percent of parliamentary seats, with a big portion going to the Muslim Brotherhood.
A proposal by the military that presidential elections not be held until late 2012 or early 2013 has further angered the opposition.
Protesters want the presidential vote to take place after parliamentary elections, which begin on 28 November and will be staggered over the next three months.
Presidential candidate Hazem Salah Abu Ismail, an ultra-conservative Salafi Islamist, told protesters: "We are demanding as the minimum that power be handed over within six months."
TV footage showed tear gas being fired into the crowds as security forces again attempted to disperse protesters from the Tahrir Square area of Cairo on Monday.
This followed fierce fighting on Sunday, in which stones and petrol bombs were thrown at police. Security forces responded with tear gas and rubber bullets.
State television reported in the early hours that a truce had been agreed between the security forces and the imam of Tahrir Square's main Omar Makram mosque, but it did not apply to streets leading to the interior ministry where much of the fighting has been taking place.
Violence also broke out in other cities over the weekend, including Alexandria, Suez and Aswan. Two people died in the clashes in Cairo on Saturday.
Major General Mohsen el-Fangari asked: "What is the point of being in Tahrir? What is the point of the strike, of the million marches? Aren't there legal channels to pursue demands?"
Nick Griffin MEP commented: "We warned that talk of an 'Arab Spring' for democracy might prove to be wishful thinking. The growing power of Islamic fundamentalists in Egypt should be of deep concern to us all. Those who supported the uprisings may find that they have unleashed an Islamic whirlwind."