The Egyptian government cannot intervene to release Ibrahim Halawa while his case is before the courts, but there may be "room" for talks on the teenager's return to Ireland after the trial, Egypt's ambassador to Ireland has said.

Mr Halawa and about 490 others are due to go on trial in Egypt Sunday on charges that include terrorism, murder and the use of explosives. The Irish-born 19-year-old, from Firhouse in Dublin, has been detained in Egypt for almost two years, having been arrested at the al-Fateh mosque in Cairo during protests against the ousting of then-president Mohamed Morsi of the Muslim Brotherhood.

The Department of Foreign Affairs says it understands from Mr Halawa’s Egyptian lawyer he may face lesser charges. Family members say they are not aware of this but remain hopeful of a positive outcome.

Amnesty International has declared Mr Halawa a prisoner of conscience and called for his release. Doughty Street Chambers, a London-based law firm representing the teenager, says his case file contains no evidence to link him to any of the crimes he is alleged to have committed.

In an interview with The Irish Times, Egyptian ambassador Soha Gendi said her government could not intervene "until the case was done" as the separation of powers precluded any interference in the judicial system.

‘Activists’

Ms Gendi said Egypt regarded it as “a terrorism case” and described Mr Halawa and his three sisters, who were also arrested at the mosque but released on bail after three months in custody, as “activists”.

She said she had done her utmost to facilitate the Irish Government and explore possibilities “to get the kid out of prison”. She “prayed” Mr Halawa would not face the most serious charges, “for us to be able to do something at a later stage”.

Asked if she could see a situation where the Egyptian government would intervene to secure his release after the trial, Ms Gendi said: “Once the case has ended and he has been either freed or [convicted] or whatever, at least there would be room so that the government of Ireland can have talks with the government of Egypt.” She added that this depended on the nature of the charges.

Ms Gendi said a number of other foreigners who were also arrested in the aftermath of Mr Morsi’s removal from power in 2013 were only released when their cases had passed from the judicial to executive authorities.

“It’s a very serious case . . . It’s not something to be taken lightly,” she said of the trial, which is scheduled to resume tomorrow after a number of adjournments. “I doubt very much that if it was the same case here, and an Egyptian citizen got entangled in this . . . that the Irish court system would just hand him freely to the Egyptian government.”