Egyptian protestors in Cairo. Photo: wiki commons.

The Muslim Brotherhood and groups opposing former Islamist-Egyptian president Mohamed Morsi called for protests in Egypt on Friday, prompting warnings from the country’s military, and a lock-down of the Sinai, after new president Adly Mansour vowed to battle for security “to the end,” Palestinian news agency Ma’an reported.

In a statement on their Facebook page, the Egyptian Army, which deposed Morsi two weeks ago in a coup, said: “The armed forces warn against any deviation from peaceful expressions of opinion, and the resort to violence. Whoever resorts to violence in Friday’s protests will endanger his life, and will be treated with utmost decisiveness, within legal bounds.”

The armed forces installed checkpoints at all entrances and exits to the Sinai to prevent any suspected militants from traveling to Cairo, an Egyptian security official told Ma’an. In Cairo, the army will secure the People’s Assembly, the Shura Council building, the Ministry of Interior and the Republican Guard House, he said, adding that army helicopters would monitor the city. The military deployed additional reinforcements in Sinai, where militants shot dead a police officer on Thursday.

Also Thursday, militants opened fire at a police unit in el-Arish and critically wounded two police officers. Abed al-Hadi, 22, was shot in the head and Mohammad al-Sibaei was shot in the shoulder and stomach. They were taken to the Mubarek military hospital, Ma’an said.

Ahead of the tense day, Egyptian President Adly Mansour spoke on state television late on Thursday. “We are at a decisive moment in Egypt’s history, which some want to steer into the unknown. We will fight the battle for security to the end. We will preserve the revolution,” he promised.

In his speech, Mansour offered an olive branch to Morsi’s Muslim Brotherhood and pledged “transitional justice,” amid calls for the prosecution of Morsi and a crackdown on the Islamists. “The framework of justice and reconciliation extends to all,” he said.

Brotherhood officials told AFP that they had insisted on Morsi’s reinstatement in a meeting with EU foreign policy chief Catherine Ashton, who visited Cairo on Wednesday.

It is “impossible to get engaged in the political process under the rules of a military coup,” a Brotherhood official, Amr Darrag, said he told Ashton.

“People are increasing on the street. The military will definitely keep making mistakes, and definitely more people will come to our side,” he added.

The Brotherhood says Morsi could call for early elections if reinstated. The interim government dismisses the proposal as unrealistic.

Mansour has issued a timetable for parliamentary elections by early next year and possibly presidential elections by May. In the meantime, an interim government sworn in on Tuesday will try to tackle the deteriorating economy that fueled the mass protests against Morsi that led up to his overthrow.

Ma’an said the Egyptian government has received $12 billion in pledges of emergency assistance from Gulf Arab states since the coup.