Egypt's security forces were on high alert Monday ahead of pro-democracy protests to mark the second anniversary of former president Hosni Mubarak's ouster, a police official told AFP.
Authorities have boosted security around the presidential palace, the interior ministry and around Tahrir Square, as well as around key public installations, the official said.
Marches are due to set off at 5:00 pm (1500 GMT) from several locations in the capital towards Tahrir -- the epicentre of protests that toppled Mubarak-- and the presidential palace where violent, sometimes deadly, protests have been staged against Islamist President Mohamed Morsi.
"There will also be extra security around the main metro stations after some groups threatened to block the tracks," the official said.
Opposition parties and movements have called for a day of action, demanding Morsi fulfill the goals of the revolution that brought him and his long-banned movement, the Muslim Brotherhood, to power.
Two years ago, Egyptians poured into the streets to celebrate Mubarak's ouster, buoyant that democratic change was possible.
The 84-year-old's spectacular fall from grace in a popular revolt sent shock waves across the Middle East and beyond when he announced his resignation on February 11, 2011 after an 18-day popular revolt.
But two years later, many are angry that the main goals of the revolt -- freedom and social justice -- have not been achieved and that the country is more polarised between Morsi's mainly Islamist supporters and a wide-ranging opposition.
Among the key demands of Monday's protests are a new unity government, amendments to a controversial Islamist-drafted constitution and the sacking of the prosecutor general.
In recent months, Egypt has witnessed violence, insecurity and price hikes, fuelling the political turmoil already plaguing the country.