CAIRO — Egypt’s capital boiled Wednesday as protesters supporting and opposing President Mohamed Morsy geared up for more demonstrations.

People angered by Morsy continued a sit-in in Cairo’s Tahrir Square, where drama surrounding Egypt’s painful political power struggle plays out daily, after a night marked by an outbreak of violent clashes outside the presidential palace.

A few dozen protesters and a scattering of tents remained outside the Itihadiya palace Wednesday morning, and opposition forces called for a march toward the palace later.

Read more: Q & A: What’s driving Egypt’s unrest?

However, witnesses and state-run Nile TV said Morsy supporters who gathered in front of the presidential palace Wednesday afternoon had pulled down the opposition protesters’ tents.

The Muslim Brotherhood, the pro-Morsy Islamist movement, called the rally in support of the country’s leader and against his foes in the street.

The group urged Egyptians to protest the “thuggish breaches that were carried out by certain groups yesterday who thought that they could shake down the legitimacy (of the president) and impose their views by force.”

“By the grace of God, the Egyptian people will be able to protect this legitimacy, its constitution and its institutions,” said a press release on the Muslim Brotherhood’s Facebook page.

Many in Egypt believe a new draft constitution in the country, which will be put to a popular vote December 15, is unfair in its wording, and is an attempt by Morsy to grab more power.

But Vice-President Mahmoud Mekki told reporters Wednesday that the referendum would be held as planned.

“Saying the referendum will be held on time is not being stubborn,” he said. “The president has backtracked from decisions before; he’s not a stubborn character.”

Mekki suggested political groups could put forward written proposals to amend the controversial constitutional articles at the first parliamentary session. According to the draft constitution, amending constitutional articles requires the approval of two-thirds of lawmakers.

Mekki said disagreements involve a dozen or so articles in the draft constitution, and that some objections have to do only with the wording rather than the content.

He said dialogue was important to figure out what would happen if the referendum results in a “no” vote.

How Egypt’s political power struggle ends could have repercussions that ripple across a region already wracked with trouble. In nearby Gaza and Israel, tensions remain high after last month’s fighting. In Syria, a civil war still rages.

Egypt’s presidential office has urged those taking part in the protests to keep them peaceful.

Police fired tear gas Tuesday night after protesters broke through barbed wire around the palace building and hurled chairs and rocks at retreating officers. After the initial clashes, police withdrew behind fences and the large demonstration was peaceful for several hours.

Thirty-one protesters were injured overnight, said Health Ministry spokesman Khaled al-Khataib. At least 40 police officers were injured in clashes outside the palace, Interior Ministry spokesman Alaa Mahmoud said.

Yassir Ali, a spokesman for the presidential office and the vice-president, told reporters Wednesday that the presidential office had ordered the security forces at the palace “to protect the protesters and keep them safe.”

“The orders to the security forces were not to confront (them), (but) to preserve the lives of the protesters and to prevent any clashes between the security forces and the protesters,” Ali said.

“Some protesters violated the peaceful manner of the protests without any reason, destroying some cars, and injuring our employees and the workers in the presidential office.”

Morsy was not at the palace when the protesters descended, his office said. He was out meeting with government officials, they said.

CNN iReporter Maged Eskander, who was at the protest Tuesday night, said the atmosphere outside the palace was electric despite the late hour.

“The police were in a large perimeter around protesters and the palace at the beginning, but when the protesters reached the wire fences and walls the police went back inside the palace,” he said.

Protesters managed to get right up to the entrance of the palace and spray slogans on the walls, calling Morsy a “liar” and decrying the Muslim Brotherhood party, he said.

Eskander, a 38-year-old architect from Cairo, predicts even bigger protests for Friday.

More violence broke out at the headquarters of the Freedom and Justice Party in Menia, south of Cairo, late Tuesday. The Freedom and Justice Party — the political wing of the Muslim Brotherhood — had been the party of Morsy before he became president.

Party head Dr. Hussein Sultan said the front of the headquarters was damaged, and at least one protester fired a shot in the air.

Eighteen Egyptian parties and movements are taking part in the sit-in protest in Tahrir Square Wednesday, according to EgyNews.

A number of media organizations also continued a protest over the country’s new draft constitution and an edict Morsy issued nearly two weeks ago to expand his powers.

Four privately owned satellite TV channels said they would go off-air for a period Wednesday evening, a day after 11 partisan and independent newspapers suspended publication. They are concerned that the constitution does not sufficiently protect freedom of the press.

Egypt’s National Salvation Front, an opposition group, issued an ultimatum to Morsy in the early hours of Wednesday, saying he must agree to meet in a few days or expect a massive march to the presidential palace and Tahrir Square on Friday, EgyNews reported.

The National Salvation Front was recently formed as a coalition of several liberal parties and prominent political figures including Amr Moussa, Hamdeen Sabbahi, Mohamed ElBaradei and Usama Ghazali Harb.

The group issued a statement saying “the Egyptian people expressed their solid persistence in rejecting the Constitutional Declaration and the attempts to bring back the rule of tyranny and that there is a need to achieve the objectives of the revolution of January 25 and the aspirations for full freedom, social justice and human dignity.”

It warned that it would hold Morsy responsible for “these dangerous repercussions,” and added that “if the president doesn’t listen to the demands of the people, he risks losing his legitimacy.”

— CNN’s Reza Sayah and journalists Mohamed Fadel Fahmy and Sara Sirgany reported from Cairo, Joe Sterling, Saad Abedine and Yousuf Basil reported from Atlanta, and Laura Smith-Spark and Sarah Brown reported from London.