At least 10 people were killed when opponents and supporters of Egypt's deposed president, Mohamed Morsi, clashed after the army announced his removal on Wednesday, state media and officials said.
Gunfire broke out as rocks and bricks flew during fighting in Alexandria, witnesses said.
At least three people were killed in the Mediterranean city, state news agency MENA reported. An earlier report said at least 50 people were wounded.
One of the dead was a woman stabbed in the stomach, MENA said. The other two were men hit by birdshot.
"We are dealing with the situation. ... We have called for security reinforcements in the area," said senior police officer Sherif Abdelhamid.
Four people were also killed in clashes in the northern city of Marsa Matrouh, the state governor said.
Governor Badr Tantawi told Reuters by telephone from the Mediterranean city close to the Libyan border that the dead were Morsi supporters.
Three people were also killed in the southern Egyptian city of Minya, including two police, MENA said. It said 14 people were wounded.
Dozens more were wounded in Fayoum, south of Cairo, where unidentified assailants broke into the local offices of the Freedom and Justice Party, the Brotherhood's political wing, MENA said.
The attackers looted the headquarters and set them on fire, it said.