Amnesty International says there is evidence clearing Irishman Ibrahim Halawa of accusations that have seen him jailed for nearly two years in Egypt.

The human rights group says eye witness accounts disprove the authorities' claims that protesters at a mosque in Cairo exchanged fire with security forces in August 2013.

19-year-old Ibrahim Halawa was arrested during the demonstration which was organised in protest at the ousting of President Mohamed Morsi.

His three sisters were also detained for a time but Ibrahim is still in custody awaiting trial along with 493 other people.