Protesters denouncing Egypt's Islamist president have hurled stones and firebombs through his palace gates.
The demonstrators clashed with security forces who fired tear gas and water cannon as more than a week of political violence came to Mohammed Morsi's symbolic doorstep for the first time.
The march on the palace in an upscale district of the capital Cairo was part of a wave of demonstrations in cities around the country called by opposition politicians, trying to wrest concessions from Mr Morsi after around 60 people were killed in protests, clashes and riots.
But many of the protesters go further, saying he must be removed from office, accusing his Muslim Brotherhood of monopolising power and failing to deal with the country's mounting woes. Many have been further angered by Mr Morsi's praise of the security forces after the high death toll, which is widely blamed on excessive use of force by the police.
In a statement issued amid the clashes, Mr Morsi said "political forces involved in incitement" are responsible for the violence and spoke of an investigation. He called on all factions to condemn what he called an attempt to break into the palace and said security forces would "act decisively to protect state institutions".
The streets outside the presidential palace - where Mr Morsi was not present - were a scene of mayhem after nightfall. Police fired dozens of volleys of tear gas at a time, pushing the crowds away from the palace gates. Flames rose as security forces set fire to protest tents, sometimes by rolling tyres that protesters had set ablaze into them. Young protesters hurled stones, banged on metal fences and threw fireworks, flashing laser pointers through the smoke.
"People are here for many reasons but I came here because I want to get rid of this regime," said Ahmed Hamdi, an 18-year-old protester, who wore thick gloves so he could pick up tear gas canisters and throw them back at police.
The fighting started when a crowd of several thousand marched to the palace chanting "the people want the fall of the regime" and "leave, leave, Morsi".
Security forces allowed them to reach close to the main gate, and some protesters hurled shoes and stones through the fence into the grounds. At first police and Republican Guards inside did not respond, but when several firebombs were thrown over the fence the security forces unleashed water cannon, then tear gas, then riot police descended on the streets outside the palace.
After several hours, a huge barrage of tear gas sent protesters scattering and riot police pushed down side streets to chase them. More than 40 people were hurt in the clashes, according to security officials.