Story highlights Supporters and opponents of Morsy clashed near Cairo's Tahrir Square

One person dead and 26 others injured, an emergency official said

The clashes come nearly three weeks after Morsy was forced out of office

Supporters and opponents of deposed Egyptian president Mohamed Morsy clashed near Cairo's Tahrir Square on Monday, leaving one person dead and 26 others injured, an emergency official said.

In one incident, a gunman opened fire near the square with an automatic weapon, and at least two people dropped to the ground, a witness told CNN. It wasn't clear which side the gunman belonged to.

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At least some of the clashes occurred when Morsy supporters who had been marching toward the U.S. Embassy shifted toward the square, where some Morsy opponents were, witnesses said.

Some Morsy supporters had gathered outside the U.S. Embassy on Monday but were dispersed by Egyptian security forces, who fired tear gas at them, state-run EGYNews reported. The embassy is about 1 kilometer from Tahrir Square.

The clashes come nearly three weeks after Morsy, backed by the Muslim Brotherhood, was forced out of office by the Egyptian military..

Egypt has been on edge ever since, with dozens reported killed and thousands injured in protests.