Cairo - The Muslim Brotherhood's leader made an unusually harsh attack on Egypt's military chief on Thursday, saying his ouster of President Mohammed Morsi was worse than destroying the Kaaba, Islam's holiest shrine.
The analogy appeared aimed at whipping up religious sentiments on the eve of mass rallies promoted by General Abdel-Fattah el-Sisi as a show of support for planned action by the military and the police to stop "violence and terrorism" by Morsi's mainly Islamist supporters.
Divisions between the two sides grew even more entrenched as the youth group behind the wave of protests that led to the 3 July military coup against Morsi threw its support behind the military, urging Egyptians to participate in Friday's demonstrations.
"Whoever wants to genuinely complete the revolution must be out in the squares and in all the provinces," said Mahmoud Badr, spokesperson for Tamarod, or Rebel in Arabic.
El-Sisi's call for a massive turnout on the streets has widely been seen as a prelude to a crackdown on the Muslim Brotherhood and other Islamists who have been camped out for about a month to call for Morsi's return.
Clashes have frequently erupted between the protesters and authorities and attacks by Islamic militants in the Sinai Peninsula have surged since his ouster.
On Thursday, two border guards were killed and three others wounded when suspected militants fired rockets at their checkpoint in the Sinai town of Sheikh Zweid, a stronghold of radical Islamists.
Islamists also planned pro-Morsi rallies on Friday, raising fears of more street battles.
Nearly 200 people have been killed in the latest wave of violence to roil Egypt since the February 2011 toppling of autocrat Hosni Mubarak amid a popular uprising.
Egypt's highest security body, the National Defence Council, said authorities were committed to ensuring the safety of all peaceful protesters but warned that no tolerance would be shown to anyone who threatens security.
It also pledged that authorities would stay within the law and respect human rights with any measures taken to end the "terrorising of citizens and breaking the law".
Brotherhood leader Mohammed Badie's statement comparing the coup and the hypothetical destruction of the Kaaba takes to a new level the enmity between the camp of Islamists led by the Brotherhood and their opponents.
Badie, who has an arrest warrant against him for allegedly inciting violence, also called el-Sisi a "traitor" and urged him to repent.
"I swear by God that what el-Sisi did in Egypt is more criminal than if he had carried an axe and demolished the holy Kaaba stone by stone," Badie said.
Former Prime Minister Hesham Kandil broke his silence since Morsi's ouster, issuing a videotaped and written statement in which he came to the defence of his patron, portraying him as a patriot who tirelessly worked for Egypt's prosperity and independence.
He also said Morsi had shown flexibility in the final days of his one-year rule, agreeing to a referendum on whether early presidential elections be held but only after parliamentary elections, which were due to be held later this year.
Kandil said the army chief insisted in a meeting with himself and Morsi the day before the coup that the vote be held in two weeks, which Morsi rejected on the grounds that the political climate was not suitable and the vote's fairness could not be guaranteed.
Before he was ousted, Morsi rejected calls to dismiss Kandil, a fellow Islamist, because of his perceived inability to effectively tackle any of Egypt's pressing problems, including tenuous security, a woeful economy, rising unemployment and fuel shortages.
The National Defence Council
The National Defence Council, which issued its statement after meeting late on Wednesday, also sought to reassure Egyptians that el-Sisi's call for rallies was not a bid to secure a popular cover for extrajudicial measures or gross human rights violations against Islamists.
The council is currently led by interim President Adly Mansour and includes the prime minister and the defence and interior ministers.
Some pro-democracy activists have raised concerns about the military's call, recalled the human rights abuses, including torturing detainees, blamed on the armed forces during its direct rule for nearly 17 months after Mubarak's ouster.
"I hope that the voice of the people tomorrow will be loud and resounding, but also peaceful," interim Prime Minister Hazem el-Beblawi told reporters on Thursday. Clearly addressing the secular and liberal camp, he said: "Whoever wants to reassert the civilian state must come out in force."
El-Beblawi also commended el-Sisi's call for the rallies, calling the general a "cornerstone in the defence of the civilian state."
"Tomorrow is the day for the expression of views, freely and responsibly. Whoever tries to spoil the party will be dealt with firmly," he said.