Stan Mallon is expected to contest the charges

The US Federal Court in Chicago heard allegations on Tuesday that computer discs seized from Mr Mallon's office and home in Crumlin, County Antrim, contained pictures of naked children and emails to at least one young girl.

Assistant US Attorney Markus Funk, said the material was of an "explicit nature".

Mr Funk said 30 disks were found at Mallon's office. Some of them contained pictures of naked girls and emails to minors, he added.

Mr Funk said a further 300 discs were taken from Mr Mallon's home, 10 of which, he said, contained "exploitative material".

Last Friday afternoon, Northern Ireland police assisting the investigation had searched Mr Mallon's home and removed his computer, videos, and a number of CDs.

Members of Mr Mallon's family were in court on Tuesday to hear the evidence against him.

Mr Mallon has been refused bail.

The judge at the US Federal Court described him as a "predator and a danger to the community".

The judge also said he believed there was a risk Mr Mallon might leave the United States, if bailed.

The father of five is being held at the Metropolitan Correctional Centre in Chicago.

If convicted, Mr Mallon could face up to 15 years in prison.

His solicitor has said he will contest the charges.

The Ulster Scots Agency is one of the cultural cross-border bodies set up under the Good Friday peace agreement.