William Hague has urged the Egyptian authorities to ensure an "inclusive" transition to democracy after protests against president Mohamed Morsi turned violent.
The Foreign Secretary urged both sides to show restraint amid clashes over wide-ranging new powers taken by president Mohamed Morsi and a controversial draft constitution.
Rocks, firebombs and sticks were used as weapons in fighting between supporters and opponents outside the presidential palace in Cairo.
It came as three presidential advisers quit over his handling of the crisis.
Mr Hague said: "I am concerned by reports of violent clashes following earlier peaceful protests in Cairo. I urge all sides to show restraint.
"The UK remains committed to supporting Egypt's political transition and strengthening democracy. We are in close contact with both the Egyptian authorities and leaders of the opposition.
"We call on the Egyptian authorities to make progress on transition in an inclusive manner which allows for a constructive exchange of views.
"We urge all parties to resolve their differences through a process of dialogue which allows all voices to be heard."