CAIRO (AFP) - The office of President Mohamed Morsi said on Sunday dialogue is the only way out of Egypt's political crisis, as tens of thousands took to the streets to demand the Islamist leader's ouster.

"Dialogue is the only way through which we can reach an understanding... The presidency is open to a real and serious national dialogue," presidential spokesman Ehab Fahmy told reporters. He urged protesters to maintain "the peaceful nature" of their protest, pointing to the anti-Morsi rallies as proof of freedom of expression in Egypt.

Tens of thousands took to the streets across the country to demand early presidential elections in a massive expression of opposition to Mr Morsi and his Muslim Brotherhood movement. The President's supporters have vowed to defend his legitimacy to the end.