At least 200,000 Islamists demonstrated in Cairo on Saturday in support of President Mohamed Morsi, who is rushing through a constitution to try to defuse opposition fury over his newly expanded powers."The people want the implementation of God's law," chanted flag-waving demonstrators, many of them bussed in from the countryside, who choked streets leading to Cairo University, where Morsi's Muslim Brotherhood had called the protest.The numbers swelled through the afternoon, peaking in the early evening at at least 200,000, said Reuters witnesses, basing their estimates on previous Cairo rallies. The authorities declined to give an estimate for the crowd size.Morsi was expected later in the day to set a date for a referendum on the constitution hastily approved by an Islamist-dominated drafting assembly on Friday after a 19-hour session."We will certainly present the constitution to the president tonight," Mohamed al-Beltagy, a Muslim Brotherhood leader and a member of the constituent assembly, told Reuters.Morsi plunged Egypt into a new crisis last week when he gave himself extensive powers and put his decisions beyond judicial challenge, saying this was a temporary measure to speed Egypt's democratic transition until the new constitution is in place.His assertion of authority in a decree issued on Nov. 22, a day after he won world praise for brokering a Gaza truce between Israel and the Palestinian Islamist Hamas movement, dismayed his opponents and widened divisions among Egypt's 83 million people.Two people have been killed and hundreds wounded in protests by disparate opposition forces drawn together and re-energised by a decree they see as a dictatorial power grab.Tens of thousands of Egyptians had protested against Morsi on Friday. "The people want to bring down the regime," they chanted in Cairo's Tahrir Square, echoing the trademark slogan of the revolts against Hosni Mubarak and Arab leaders elsewhere.Rival demonstrators threw stones after dark in the northern city of Alexandria and a town in the Nile Delta. Similar clashes erupted again briefly in Alexandria on Saturday, state TV said.