The court hearing of Egypt's former president Hosni Mubarak over murder charges during the 2011 uprising began early on Wednesday without the ex-president showing up.
Mubarak was due testify in his own defence for the first time since he was brought to trial in late 2011 after the 18-day popular revolt forced him out.
Mubarak's defence lawyer and a senior security official told the presiding judge Mahmoud El-Rashidy in a live TV broadcast that the early morning fog has grounded a helicopter meant to bring the former leader.
The time of Mubarak's arrival to the courtroom, at a police academy on the eastern outskirts of Cairo, is so far unknown, the security official told the judge.
Mubarak is being retried, alongside his interior minister and six of his top aides, for complicity in the killing of around 850 demonstrators during the 18-day popular revolt in 2011 that ended his 30-year reign.
Present at the court hearing on Wednesday were Mubarak's sons Alaa and Gamal, who also face trail along with their father over graft charges, Al-Adly and his aides.
His sons are also scheduled to give their personal pleadings on Wednesday.