Minister for Foreign Affairs Micheál Martin has pledged to do everything possible to secure the release of two Goal aid workers missing for almost seven weeks.
Sharon Commins (32), from Clontarf, Dublin, and her Ugandan colleague Hilda Kawuki (42) were taken by a gang of armed men from a Goal compound in north Darfur on July 3rd.
Speaking on RTÉ Radio today, Mr Martin said there was concern about the length of time the women had been held.
"Sharon and Hilda were there purely for humantiarian purposes. We know from local contacts that they were held in the highest esteem in Darfur," Mr Martin said.
"We will spare no effort to work towards the release of both Sharon and Hilda. We are using all channels we possibly can."
An inter-departmental operation involving gardaí, defence forces and the Department of Foreign Affairs was in place, he said.
Two teams sent out to Sudan, in Khartoum and El Fasher, when the women were first taken are reporting to him on a daily basis, he said, and close contact with Commins family is being maintained.
Mr Martin said the situation was complex, and he did not want to say anything that would make it more difficult or raise hopes until there was something definite to report.
"Over the last number of weeks we've had highs and lows on this. It's been to some extent depending on the information that comes through - one is hopeful some days, more hopeful than others," he said.