US authorities are seeking the extradition of a 28-year-old Irishman alleged to be involved in the distribution of online child pornography.

Eric Eoin Marques was described in the High Court yesterday by an FBI Special Agent as "the largest facilitator of child porn on the planet."

Mr Marques appeared before Mr Justice Paul Gilligan on foot of an extradition request by the FBI and was remanded in custody until next Thursday.

The court heard Mr Marques, who has both Irish and US citizenship was arrested on a Maryland, US warrant that records charges of distributing and promoting child pornography on the internet.

Mr Justice Gilligan refused to grant Mr Marques bail until the extradition request has been determined.

US authorities are seeking his extradition on four charges.

Mr Marques, with an address at Mountjoy Square in Dublin, is charged with distributing, conspiring to distribute, and advertising child pornography.

It was also alleged he aided and abetted a conspiracy to advertise child pornography and the court heard that if convicted he faces up to 30 years in prison.

The charges relate to images on a large number of websites described as being extremely violent, graphic and depicting the rape and torture of prepubescent children.

Barrister Ronan Kennedy, counsel for the Attorney General, said Mr Marques was arrested on Thursday on foot of an extradition warrant that was issued by a US court on 29 July.

Investigating gardaí and the FBI both objected to bail being granted.

It was claimed Mr Marques, whom it is alleged had travelled extensively, represented a flight risk and may try to interfere with evidence.

The court heard evidence that large sums of money had passed through Mr Marques' bank accounts, including large payments sent to accounts in Romania.

The court also heard that a search of Mr Marques's computer revealed he had made inquires about how to get a visa and entry into Russia.

He has no previous convictions nor had he ever come to the attention of the authorities before.

The FBI Special Agent referred to him as having been "anonymous."

Mr Marques told the court he was born in the US but has lived in Ireland since he was five.

He said his father is Brazilian and his mother is Irish. He said he had visited Romania a few times, and had friends and an ex- girlfriend there whom he was helping out financially.

Mr Marques said he was last in Romania a few weeks ago when he withdrew €6,000 from his credit card to help a friend start a business.

He also told the court that several weeks ago he searched online about Russian visas out of curiosity due to the issues surrounding former US spy contractor Edward Snowden,

Through his counsel, Remy Farrell SC, Mr Marques said he would abide by any bail terms and conditions set down by the court, and had surrendered both his Irish and US passports to the gardaí.

Refusing bail Mr Justice Gilligan said he accepted the evidence that Mr Marques was a flight risk.

He remanded Mr Marques in custody to a sitting of the High Court on 8 August.