Cairo: Egyptian opposition activists have started an open-ended strike outside the presidential palace where thousands of demonstrators Tuesday evening gathered to protest President Mohammad Mursi’s decree expanding his powers and call for a public vote on a highly controversial referendum.

“The people have made a great victory today,” the National Salvation Front, an opposition coalition, said following a crisis meeting. The alliance was set up last month after Mursi granted himself sweeping new powers making all his decisions and laws above judicial scrutiny.

“The front gives Mursi until Friday to fulfil Egyptians’ demands,” said Sameh Ashour, a member of the alliance that also comprises Nobel laureate Mohammad Al Baradei and former presidential contender Amr Mousa.

Ashour said there would be escalatory action if Mursi did not reverse his decree and call for a December 15 referendum on the draft constitution, Egypt’s first since Hosni Mubarak’s ouster in February last year.

Protesters, who have been camping in Cairo’s Tahrir for nearly two weeks, said they would move their strike to outside the presidential palace in the eastern quarter of Heliopolis.

Mursi, Egypt’s first elected Islamist president, had to leave the palace shortly after the start of Monday’s protest for security reasons, according to the local media.

“The decision to evacuate the president was made ahead of any potential risk or developments,” a senior security source told the website of the state-run newspaper Al Ahram. Mursi left through a back door of the palace, according to the source.

The riot police positioned around the palace fired tears gas and shot in the air after some protesters attempted to break through the barbed wire set up around the palace. Clashes followed between the two sides in which 29 civilians were injured, according to the health ministry.

Tensions were shortly defused after the police retreated on the site where demonstrators chanted slogans    against Mursi and his group, the Muslim Brotherhood.

Mursi’s decree has sharply split Egypt and sparked clashes between his backers and opponents, leaving at least three people dead.

Mursi said his measures are temporary until a new constitution is approved and an elected parliament is in place.