CAIRO (REUTERS) - Thousands of Egyptians marched and chanted against Islamist President Mohamed Mursi in cities across the country on Friday, burning tyres and throwing petrol bombs in some areas.

Fierce protests erupted late last month over what demonstrators saw as Mursi's attempts to monopolise power as well as wider political and economic grievances, but the unrest had calmed over the last week.

The main opposition alliance, which signed an agreement with the ruling Muslim Brotherhood last week rejecting violence, had not called for marches on Friday.

While the number of protesters has dwindled, distrust of Mursi and the Brotherhood and a sense of political and economic malaise have continued to bring people to the streets.

At least 59 people died in the demonstrations between Jan 25, second anniversary of the uprising that toppled President Hosni Mubarak two years ago, and Feb 4.

The most violent clashes on Friday were in the Nile Delta town of Tanta, hometown of an activist, 23-year-old Mohamed el-Gendi, who was buried there this week after being beaten to death by security men in Cairo.

Television footage showed scores of protesters lobbing petrol bombs at riot police, who responded with tear gas to scatter the demonstrators.

"Down, down with the rule of the Supreme Guide," protesters chanted, referring to Mohamed Badie, leader of the Brotherhood, which has dominated Egypt's politics since the fall of Mubarak.

In another Delta town, Kafr el-Sheikh, dozens of protesters pelted police with rocks and tried to storm a government building to demand the removal of the provincial governor, the state news agency MENA reported.

Thousands of protesters also gathered in Cairo's Tahrir Square, the epicentre of the 18-day revolt that toppled Mubarak, and outside the presidential palace, where witnesses said some threw petrol bombs over the gate.

At Tahrir Square's subway station, demonstrators stopped a main subway line by climbing onto the tracks, MENA reported.

In the town of El-Santa in Gharbiya province, protesters threw rocks at the offices of the Freedom and Justice Party, the Brotherhood's political party, MENA reported.