CAIRO — Egyptian President Mohammed Morsi defied mass protests calling for his resignation just hours before the expiration of a military-imposed deadline for him to end the political crisis or step down.

Clashes between Morsi supporters and opponents intensified with at least 23 people killed in violence over the past day, according to state-run media. The army said July 1 it would impose its own plan if Morsi didn’t end the turmoil and meet the people’s demands within 48 hours.

That deadline is due to expire between 3:00 p.m. and 5:00 p.m. local time Wednesday. The unrest helped to send West Texas Intermediate crude oil prices above $100 a barrel for the first time since September.

“If the price of safeguarding legitimacy is my own blood, I am ready to sacrifice it,” Morsi said in a speech broadcast on state television. “There is no alternative to constitutional legitimacy.”

Morsi’s defiant comments will probably increase tensions already running high as the expiration of the military ultimatum nears. They come as a political showdown between his supporters and opponents, both rallying on the streets, escalates amid sporadic violence.

Sixteen people were killed and 200 injured in battles near Cairo University between Morsi’s backers and opposition protesters, the state-run Middle East News Agency reported, citing the Health Ministry. In Giza province, at least seven people were killed, Health Ministry spokesman Yehya Mousa said.

‘SPONTANEOUS VIOLENCE’

“Spontaneous violence will erupt between supporters and opponents given the tense environment,” Ziad Akl, senior analyst at Al Ahram Center for Political and Strategic Studies in Cairo, said by phone. If unrest escalates, “the army will step in.”

The state-run Ahram newspaper reported, without saying where it got the information, that if Morsi didn’t resign, he may be forced to leave office through an army plan. The military plan would also include replacing the country’s constitution and installing an interim government to be headed by a military leader, Ahram reported.

Egyptian army spokesman Ahmed Mohamed Ali said it was “too early” to talk about the army’s plan, saying the deadline’s existence doesn’t mean the military has already prepared a scenario for action.

“After the deadline, the army will call different parties for talks to set the road map,” he said by telephone. “The army will not set the road map unilaterally.”

Before Morsi’s speech, a comment posted on the Islamist president’s official Twitter Inc. account said Morsi “asks the military forces to withdraw its ultimatum and rejects any domestic or foreign dictates.”

The deadline signaled that the military, like the opposition, had lost patience with a government that opponents blame for polarization that’s marred the transition from Hosni Mubarak’s autocratic rule.

‘CIVIL WAR’

“Instead of announcing his resignation upon popular demand,” Morsi’s comment on Twitter “is clearly pushing the country toward the verge of a civil war,” Khaled Dawoud, spokesman for the National Salvation Front opposition bloc, said in a telephone interview. “Morsi is again acting as a president for the Muslim Brotherhood only, and not for all Egyptians.”

While many opponents welcomed the ultimatum, Morsi’s Islamist backers responded by pledging to stand firm against what they saw as a threat of a military coup.

“I don’t allow or accept to have anyone saying talk that runs contrary to legitimacy or taking any steps or measures that shake this legitimacy,” Morsi said in his televised speech.

“This is rejected,” he said three times. “Legitimacy is the real, but even the only, guarantee to ensure that there is no violence.”

The June 30 Front, an amalgam of opposition groups, named Nobel laureate Mohamed ElBaradei to represent it in talks about the country’s future.

Morsi’s “days as Egypt’s president are probably numbered,” Eurasia Group Mideast analyst Hani Sabra said in e- mailed comments. “While there is still an opportunity for a negotiated settlement, it is becoming less likely.”

CABINET RESIGNATIONS

The military’s steps into the rift between the Islamist president and his opponents coincided with Morsi’s first anniversary in office — a year detractors paint as one of turmoil, deepening poverty and sectarian violence.

If Morsi “is a real patriot, he would step down, allow for new elections,” Egyptian billionaire Naguib Sawiris told Bloomberg TV Tuesday. “By staying against the will of the people, he’s just driving the country into a civil war.”

Two Morsi spokesmen, both veteran diplomats, resigned Tuesday, said a senior foreign ministry official, speaking on condition of anonymity because he wasn’t authorized to disclose that had resigned. So did the Cabinet spokesman, Ahram Gate reported, joining at least five ministers who have resigned.

SECURITY OFFICIALS

The state-run Middle East News Agency reported that Prime Minister Hisham Qandil presided over a Cabinet session that didn’t include the nation’s top security officials, the defense and interior ministers. It was the defense minister, Abdelfatah Al-Seesi, who issued the military’s ultimatum.

Gehad El-Haddad, the Muslim Brotherhood’s spokesman, used Twitter’s social media website to push back against calls for Morsi to resign and to portray the Brotherhood as aligned with the Egyptian people.

Egypt’s people “will NEVER allow anyone to bully their democratic choices & will stand firm in the face of ANYONE threatening their legitimacy,” he said in a posting to his 32,520 followers.

The protests that have pulled millions into Egyptian streets across the country leave the country with a choice, El- Haddad wrote. “This is no longer anti/pro Morsi. Choice is either Peaceful Democratic Transference of Power or Military-Backed coup. Make ur choice.”

The National Coalition for Legitimacy, an Islamist group made up of the Muslim Brotherhood and its allies, called for counter-protests.

‘DEAD BODIES’

“We swear to God, we won’t allow any coup against legitimacy, except over our dead bodies,” Mohamed El-Beltagy, a senior Muslim Brotherhood official, declared July 1 in Raba’a El-Adaweyya square, where Morsi supporters have held rallies. “Each of us must call his family and relatives and tell them get ready for the most sacred mission in Egypt’s history.’

‘‘Are you ready for martyrdom?” he asked the supporters, drawing cheers of “God is Great.”

Battles between Morsi supporters and opponents broke out Tuesday in Cairo, Alexandria, Giza and Banha, state media reported, while Al-Jazeera Mubashir Misr said that a headquarters for the Muslim Brotherhood’s Freedom and Justice Party in Fayoum was stormed.

Protesters stormed the Muslim Brotherhood headquarters in Cairo on July 1, setting its first floor ablaze. Clashes erupted between the two sides in the port city of Suez, though the unrest hasn’t affected transit through the Suez Canal, a major conduit for oil.

The armed forces said July 1 the deadline was a “last chance” and that the military would impose its own blueprint for the future if the people’s demands weren’t met. Morsi opponents were jubilant. Fireworks lit up the sky in Cairo and hundreds of thousands celebrated in Tahrir, a focal point of the nationwide protests.

Hours later, the military downplayed talk of a coup, saying it wanted only to push for a quick resolution to the current crisis.