Egyptian judicial authorities have extended deposed President Mohammed Morsi's detention period for 30 days, according to Reuters.

Morsi, who was overthrown by the army on July 3, is being held at an undisclosed location on allegations of murder and spying.

525 people are said to be killed on Wednesday, Aug 14 when security forces stormed Islamist protest camps in Cairo after a stand-off lasting weeks.

Most of the victims died in the capital but there was violence around the country on the bloodiest day since the pro-democracy uprising two years ago.

The final toll is believed far higher as scores of bodies are not registered.