CAIRO (AP) - Turmoil and uncertainty in Egypt deepened Wednesday after the country's defiant president insisted he will not step down in the face of demands by millions of protesters, vowing to protect his "constitutional legitimacy" with his life.
Overnight clashes between President Mohamed Morsi's supporters and opponents left at least 23 dead, most of them in a single incident of fighting outside Cairo University.
The violence came just hours before a military deadline was to expire Wednesday for Morsi to find a solution with the opposition or the army would impose its own political plan. The draft would see the military suspend the constitution, disband parliament and install a new leadership.
With his political fate hanging in the balance, Morsi on Tuesday demanded that the powerful armed forces withdraw their ultimatum, saying he rejected all "dictates" -- from home or abroad.
In an emotional speech aired live to the nation, the Islamist leader who a year ago was inaugurated as Egypt's first freely elected president accused loyalists of his ousted autocratic predecessor Hosni Mubarak of exploiting the wave of protests to topple his regime and thwart democracy.
"There is no substitute for legitimacy," said Morsi, at times angrily raising his voice, thrusting his fist in the air and pounding the podium. He warned that electoral and constitutional legitimacy "is the only guarantee against violence."
The statement showed that Morsi and his Muslim Brotherhood are prepared to run the risk of challenging the army. It also entrenches the lines of confrontation between his Islamist supporters and Egyptians angry over what they see as his efforts to impose control through the Brotherhood and his failures to deal with the country's multiple problems.
As anti- and pro-Morsi supporters geared for the fourth consecutive day of mass rallies Wednesday, it was clear that Egypt's crisis has become a struggle over whether a popular uprising can overturn the verdict of the ballot box.
Morsi's opponents say he has lost his legitimacy through mistakes and power grabs and that their turnout on the streets over the past three days shows the nation has turned against him.
On Tuesday, millions of jubilant, chanting Morsi opponents again filled Cairo's historic Tahrir Square, as well as avenues adjacent to two presidential palaces in the capital, and main squares in cities nationwide. After Morsi's speech, they erupted in indignation, banging metal fences to raise a din, some raising their shoes in the air in a show of contempt. "Leave, leave," they chanted.
The president's supporters also moved out in increased marches in Cairo and other cities, and stepped up warnings that it will take bloodshed to dislodge him. While Morsi has stuck to a stance that he is defending democracy in Egypt, many of his Islamist backers have presented the fight as one to protect Islam.
Political violence was more widespread on Tuesday, with multiple clashes between the two camps in Cairo as well as in the Mediterranean city of Alexandria and other cities. A march by Morsi supporters outside Cairo University came under fire from gunmen on nearby rooftops.
At least 23 people were killed in Cairo and more than 200 injured, according to hospital and security officials who spoke on condition of anonymity because they were not authorized to talk to the media. Most of the killings took place outside Cairo University in Cairo's twin city of Giza.
The latest deaths take to at least 39 the people who have died since the first day of protests, Sunday.
On Monday, the military gave Morsi an ultimatum to meet the protesters' demands within 48 hours. If not, the generals' plan would suspend the Islamist-backed constitution, dissolve the Islamist-dominated legislature and set up an interim administration headed by the country's chief justice, the state news agency reported.
The leaking of the military's so-called political "road map" appeared aimed at adding pressure on Morsi by showing the public and the international community that the military has a plan that does not involve a coup.
On his official Twitter account, Morsi urged the armed forces "to withdraw their ultimatum" and said he rejects any domestic or foreign dictates."
In the 46-minute speech Tuesday, he implicitly warned the military against removing him, saying such action will "backfire on its perpetrators."
Fearing that Washington's most important Arab ally would descend into chaos, U.S. officials said they are urging Morsi to take immediate steps to address opposition grievances, telling the protesters to remain peaceful and reminding the army that a coup could have consequences for the massive American military aid package it receives. The officials spoke on condition
of anonymity because they were not authorized to speak publicly.
Morsi's adviser Ayman Ali denied that the U.S. asked Egypt to call early presidential elections and said consultations were continuing to reach national conciliation and resolve the crisis. He did not elaborate.
The army has insisted it has no intention to take power. But the reported road map showed it was ready to replace Morsi and make a sweeping change in the ramshackle political structure that has evolved since Mubarak's fall in February 2011.
The constitution and domination of the legislature after elections held in late 2011-early 2012 are two of the Islamists' and Brotherhood's most valued victories -- along with Morsi's election last year.
At least one anti-Morsi TV station put up a clock counting down to the end of the military's ultimatum, putting it at 4 p.m. Wednesday (1400 GMT, 10 a.m. EDT), though a countdown clock posted online by Morsi opponents put the deadline at 5 p.m. (1500 GMT, 11 a.m. EDT). The military did not give a precise hour.
Morsi also faced new fissures within his leadership.
Three government spokesmen -- two for Morsi and one for the prime minister -- quit on Tuesday as part of high-level defections that underscored Morsi's increasing isolation and fallout from the military's ultimatum. Five Cabinet ministers, including the foreign minister, resigned Monday, and a sixth, Sports Minister El-Amry Farouq, also quit Tuesday.
One ultraconservative Salafi party, al-Nour, also announced its backing for early elections. The party was once an ally of Morsi but in recent months has broken with him.
In a significant move, opposition parties and the youth movement behind the demonstrations agreed that reform leader and Nobel Peace laureate Mohamed ElBaradei would represent them in any negotiations on the country's political future. The move appeared aimed at presenting a unified voice in a post-Morsi system, given the widespread criticism that the opposition has been too fragmented to present an alternative to the Islamists.