British Foreign Secretary William Hague condemned the use of violence against protesters after 65 were killed and hundreds were injured in clashes between supporters of former president Mohamed Mursi and police forces early on Saturday.

"I call on all sides to refrain from violence. Now is the time for dialogue, not confrontation. It is the responsibility of leaders on all sides to take steps to reduce tensions," Hague said in a statement.

"I am deeply concerned by recent events in Egypt, and condemn the use of force against protesters which has led to the loss of lives," he stated.

Hague called on Egypt's authorities to release political leaders detained following the July 3 events or to charge them in accordance with the law.

"Such charges must be free from any suspicion that they are politically motivated," he added.

Hague emphasized Egypt's need for a political process that includes all groups on an equal footing in order to prepare for holding early fair presidential elections which all parties can contest.