CAIRO – Egyptians delivered an angry backlash against President Mohammed Morsi and his Muslim Brotherhood on Friday, marking the second anniversary of the start of the country’s revolution with tens of thousands filling major squares and streets around the country to call for a new regime change.

Two years to the day that protesters first rose up against now-toppled autocrat Hosni Mubarak, Egypt is entrenched in the new phase of its upheaval — the struggle between ruling Islamists and their opponents, played out on the backdrop of a worsening economy.

Rallies turned to clashes near Tahrir Square and outside the presidential palace in Cairo and in multiple cities around the country, with police firing tear gas and protesters throwing stones. At least four people, including a 14-year-old boy, were killed in the day’s worst clashes in the city of Suez, where protesters set ablaze a building that once housed the city’s local government.

More than 370 were injured nationwide, the Health Ministry said, including five in Suez with gunshot wounds, raising the possibility of a higher death toll, the state news agency said.

Friday’s rallies appeared to have brought out at least 500,000 opposition supporters, a small proportion of Egypt’s 85 million people, but large enough to suggest that opposition to Morsi and his Islamist allies is strong in a country fatigued by two years of political turmoil, surging crime and a free-falling economy that is fueling popular anger. Protests and clashes took place in at least 12 of Egypt’s 27 provinces, including several that are Islamist strongholds.

“After what happened to me, I will never leave until Morsi leaves,” said protester Sara Mohammed after she was treated for tear gas inhalation at clashes outside the president’s palace in Cairo’s Heliopolis district.

“What can possibly happen to us? Will we die? That’s fine, because then I will be with God as a martyr. Many have died before us and even if we don’t see change, future generations will.”

The immediate goal of the opposition was to have a show of strength to push Morsi to amend the country’s new constitution, which was pushed through by his Islamist allies and rushed through a national referendum last month.

But more broadly, protesters are trying to show the extent of public anger against the Muslim Brotherhood, the organization Morsi hails from, which they say is acting unilaterally and taking over the state rather than setting up a broad-based democracy.

Morsi is Egypt’s first freely elected and civilian president; his four predecessors were of military background. But his six months in office have been marred by some of the worst crises since Mubarak’s ouster and divisions that have left the nation scarred and in disarray. A giant wave of demonstrations erupted in November and December following a series of presidential decrees, since rescinded, that gave Morsi near absolute powers.

The Brotherhood and its Islamist allies, including the ultraconservative Salafis, have justified their hold by pointing to their string of election victories the past year, though the opposition says they have gone far beyond what in many ways is a narrow mandate because Morsi won the presidency with less than 52 percent of the vote. Brotherhood officials have increasingly depicted the opposition as undemocratic, trying to use the streets to overturn an elected leadership.

Thursday night, Morsi gave a televised speech that showed the extent of the estrangement between the two sides. He denounced what he called a “counter-revolution” that is “being led by remnants of ousted president Hosni Mubarak’s regime to obstruct everything in the country.”

Unlike in 2012, when both sides made a show of marking Jan. 25 — though not together — the Brotherhood stayed off the streets for Friday’s anniversary. The group said it was honoring the occasion with acts of public service, like treating the sick and planting trees.