Foreign Secretary William Hague has condemned the "disproportionate use of force" by the Egyptian security forces as he issued a fresh appeal to all sides to end violence.
Mr Hague's appeal for restraint comes as supporters of the Muslim Brotherhood in the UK staged a demonstration outside Downing Street.
About 400 demonstrators gathered in Whitehall opposite Downing Street. The group of men, women and lots of young children held banners with various messages.
One man's banner said "To whom it may concern - It is a military COUP", while another banner said "Resist Egypt Coup". One woman's poster said "In the love of Egypt we are united", while another said "Sisi: Egypt's New Mubarak". One poster said "Egyptians will protect their free will at all cost".
The demonstration, which was said to be backed by British Egyptians For Democracy, featured the chant: "Cameron, Cameron, can't you see? Sisi killed democracy." They also chanted: "Sisi Sisi wait and see, Egypt Egypt will be free."
A speaker told the crowd the demonstration was not about Egypt, but "about humanity". The demonstrators chanted about how "army rule must end".
Mr Hague called for an end to the violence in a call with Egyptian foreign minister Nabil Fahmy, telling him Britain condemned all acts of violence, whether by the military or by some demonstrators protesting at the overthrow of former president Mohammed Morsi. He said that attacks on mosques and churches were "unacceptable" and called for places of worship to be protected.
Mr Hague urged the Egyptian government to return to the political road map published last month based on dialogue between parties who accepted peaceful political processes.
"The Foreign Secretary emphasised UK condemnation of all acts of violence, whether disproportionate use of force by the security forces or violent actions by some demonstrators," said a Foreign Office (FO) spokesman.
"They also discussed the recent attacks on places of worship and the Foreign Secretary stressed that attacks on mosques and churches were unacceptable and that places of worship must be protected. He underlined the need for urgent steps by all sides to end the violence and enable a return to dialogue. The Foreign Secretary also emphasised the EU's collective determination to support a peaceful resolution of the situation," he said.