British nationals have been warned to stay away from Egypt's Tahrir Square as violent clashes left at least 11 dead.
Security forces surged on thousands of protesters chanting against the ruling military council in a second day of bloody battles.
The Foreign Office amended its travel advice to warn British nationals to stay away from flash-point areas around Tahrir and the downtown area, avoid crowds and seek advice from their tour operators.
It said the embassy, near Tahrir, remains open but urged citizens seeking consular advice to call rather than turn up.
Foreign Office minister Alistair Burt said: "It is important Egypt enters the coming elections in an atmosphere of calm and mutual respect.
"The clashes occurring between police and protesters in Tahrir Square and across Egypt are deeply concerning and the loss of life and injuries deeply regrettable.
"I condemn the violence, and call on all sides to find a peaceful way forward, committing themselves to dialogue and the completion of a transfer to democratic civilian rule on the basis of a credible timetable.
"We are following events closely and our embassy is in contact with the Egyptian authorities in Cairo."