Opponents and supporters of Egyptian President Mohammed Morsi displayed strength in two areas of Cairo Saturday, the eve of a protest campaign called by the opposition to demand the Islamist leader step down, dpa reported.
Hundreds of Morsi opponents joined other protesters who have already camped in Cairo's Tahrir Square, which was the focal point of a popular uprising that forced president Hosny Mubarak to resign more than two years ago.
With army helicopters hovering over the square, the demonstrators, waved the Egyptian flag and chanted: "The people and the army are one hand."
Some Egyptians have recently said they want the army to seize power from Morsi, who belongs to the powerful Muslim Brotherhood movement.
Backers of Morsi, meanwhile, began an open-ended sit-in around a major mosque in eastern Cairo, a day after they held a huge rally to show support for the president.
They waved sticks and raised Morsi's pictures as they ran around the site, shouting, "Strength, determination and faith."
Many shops and businesses in the Egyptian capital closed for fear of violence after seven people have been killed in clashes between Morsi's opponents and backers since Wednesday, the Health Ministry said.
Several Muslim Brotherhood offices have been attacked and set on fire in the past two days.
The country's top Muslim cleric warned both sides against the danger of "sliding into a civil war."
"The incidents of violence, killing, torching and bloodshed ... are condemnable," al-Azhar Sheikh Ahmed al-Tayyeb said.
The state-run Middle East News agency said Morsi reviewed preparations with the defence and interior ministers to protect state institutions and demonstrators ahead of Sunday's protests.
Opposition protesters plan to march to the presidential palace Sunday to demand Morsi resign and call early presidential elections.
Morsi, who will have been in office for one year on Sunday, recently said called such calls were "absurd and unlawful."
Deepening divisions among ruling Islamists and the largely secular opposition have polarized Egypt, raising fears about wider street violence.
The grassroots group Tamarod, which spearheads the anti-Morsi campaign, said Saturday that it had collected more than 22 million signatures, beating the 13.2 million votes that Morsi secured in the June 2012 presidential election.
Tamarod, Arabic for rebellion, is pushing for Morsi's ouster, accusing him of mismanaging the country.
In a gesture of solidarity with Tamarod, nine secular members of the Shura Council, Egypt's Islamist-led interim parliament, said they were resigning, the state-run newspaper al-Ahram reported.
Soldiers and armoured vehicles were deployed around key state institutions in Cairo and other cities to prevent chaos like that seen during the revolt against Mubarak.
In the volatile Sinai Peninsula, gunmen shot dead a senior police officer Saturday, security officials said.
Colonel Mohammed Hani was killed in a drive-by shooting outside his house in the city of Al-Arish in northern Sinai, they said. His driver was injured.
Police arrested the suspected perpetrators two hours after the assault, the officials said without giving details.
The vast desert peninsula has been hit by security problems since Mubarak's overthrow.
As tensions mounted in Egypt, the departure terminals at Cairo's airport were packed with passengers leaving for Europe, the United States, Canada and the Gulf, airport officials said.
At least 45 US embassy officials and their families where among those who flew out after the US State Department issued a travel warning for Egypt. An American was among those killed in the protests this weeks.
US President Barack Obama expressed concern over the violent protests in Egypt and urged Morsi's supporters and the opposition to show restraint.
"Getting the political process back on track" was a priority in Egypt, where Washington would like to see both sides engaged in "more consistent conversation" on how to move the country forward, Obama said while on a visit to South Africa.
In Stockholm, three female activists staged a topless protest in its main mosque, which was described by a feminist group as a "gesture" in support of the Egyptian opposition.
The women were removed from the mosque and questioned on suspicion of disorderly conduct, a police spokesman said.
The Egyptian opposition accuses Morsi, the country's first democratically elected president, of failing to fulfil the objectives of the revolution that brought him to power.
The opposition also accuses the Muslim Brotherhood of focusing on consolidating power and failing to address Egypt's economic and social problems.
Morsi's supporters have vowed he would complete his four-year term.