Protesters in Suez set a government building on fire and tried to burn down a local office of Egypt's ruling party late on Wednesday, security sources and witnesses said.
The fire spread through parts of the Suez provincial administration office but was put out before the flames engulfed the entire building, they said.
Dozens of protesters also threw petrol bombs at the National Democratic Party office but failed to set it alight. Police fired teargas to push the demonstrators back.
Officials in the city 80 miles (129 km) east of the capital Cairo ordered that shops be closed after incidents of looting were reported. Clashes with police left some 55 people injured, according to witnesses.
The government stepped up security at all major buildings in the area, said a Reuters reporter based in Ismailia north of Suez.
Suez lies at the southern end of the Suez Canal, which leads from the Mediterranean to the Red Sea. There was no indication that traffic through the canal was affected.
