Ten major Egyptian rights groups on Wednesday urged an appeals court to free Alaa Abdel Fattah, a leading dissident in the 2011 uprising that toppled strongman Hosni Mubarak.

The court of cassation, which handles appeals, is set to rule Thursday on the activist's case after he was sentenced to five years in prison over an illegal protest.

The rights groups urged the court to "uphold justice and the rule of law and to rectify gross violations of the law" which they say led to Abdel Fattah's imprisonment.

Once described by the authorities as an "icon of the revolution" of 2011, 35-year-old Abdel Fattah was among dissidents arrested after a November 2013 protest outside parliament in defiance of a law that banned all demonstrations except those authorised by police.

He had initially been sentenced to 15 years in jail but a court ordered a retrial and he later received a sentence of five years in prison, of which he has served three and a half.

The rights groups said the trial had been "full of violations of the law and without procedural safeguards".

Recent weeks have seen a growing social media campaign for the activist's release, using the hashtag "#Free_Alaa".

The case was among the most prominent in a series of trials of secular dissidents who have been jailed along with thousands of Islamists since the army overthrew Islamist president Mohamed Morsi in July 2013.

Source:AFP