The Irish foreign minister has expressed concern after the trial of an Irishman, who was been imprisoned in Egypt for more than three years, has been adjourned again.
Ibrahim Halawa, 20, the son of Ireland's most senior Muslim cleric, was arrested during anti-government protests in Cairo in August 2013.
He was due in court on Saturday.
Irish Foreign Minister Charlie Flanagan said his priority was to see Mr Halawa return to Ireland as soon as possible.
Mr Halawa was due to appear along with 463 others, charged with inciting violence, rioting and sabotage relating to the protests in Cairo.
Mr Flanagan said: "Our understanding is that the trial has been adjourned until 13 December as a number of the defendants were not present in the court. This is linked to heightened security concerns in Cairo, following planned protests in recent days."
The minister said the Irish Ambassador to Egypt, Damien Cole, led an embassy observer team at the hearing on Saturday and said officials from the embassy had attended all hearings to date.
Mr Flanagan said the Irish government would continue to use "every possible opportunity to underline our concerns" about this case to the Egyptian authorities, both "bilaterally and with the EU and other partners".
"Ibrahim's lawyers have submitted an application for his return to Ireland under Egypt's Decree 140 Law, and the government is giving this initiative its full support," he said.
"The Taoiseach [Irish prime minister] has been in direct contact with President al-Sisi asking him to give positive consideration to the Decree 140 application. I have had a number of contacts with my Egyptian counterpart, Foreign Minister Sameh Shoukry, endorsing the application for Ibrahim's immediate release.
"I discussed the case with Minister Shoukry most recently on November 1st, when I once again repeated our call for this citizen's immediate return to Ireland."
Mr Flanagan said "in light of today's developments", the Irish government would be pursuing further contacts at the highest levels with Egypt to address Mr Halawa's continued detention and to again call for his immediate return to Ireland.
"I want to reaffirm the government's and my own personal commitment to secure Ibrahim Halawa's return to Ireland as soon as possible and we will be continuing to examine and explore all possible options for action that can help to achieve that objective," he added.
Mr Halawa's solicitor, Darragh Mackin, said it was "deeply disappointing" but "entirely unsurprising" that his trial had been adjourned again.
"This is indicative of the fact that Ibrahim cannot get a fair trial, and therefore it makes the outstanding application for a presidential decree even more important," he said.
Mr Mackin said he had been in contact with the Irish department of foreign affairs and the taoiseach's office to "ensure that urgent action is taken to ensure that maximum pressure is brought to bear in the resolution of the outstanding decree".
Three months ago, Egypt rejected a call from the Irish government for the immediate release of Mr Halawa, whose family live in Dublin, under presidential decree.
The Egyptian government has also rejected allegations by the United Nations about his treatment in prison.
Mr Halawa's trial has now been postponed 16 times.
Earlier this month, Amnesty International held a vigil at Stormont to show support for a campaign calling for Mr Halawa's immediate release.
Mr Halawa's sister, Khadija, attended and called on the Irish government to do more to put pressure on the Egyptian authorities to release her brother.
The family has denied claims that Mr Halawa is a member of the Muslim Brotherhood, Egypt's oldest and largest Islamist organisation.
The Egyptian government has declared it a terrorist group, a claim the organisation rejects.
More than 1,000 people have been killed and 40,000 are believed to have been jailed since President Abdul Fattah al-Sisi led the military's overthrow of Mohammed Morsi, Egypt's first democratically elected head of state, in 2013.