The Justice Minister says he has been given some reassurances and clarity from the US government over its online surveillance operation.

Alan Shatter was speaking following a meeting between the EU and US at Dublin Castle where the PRISM programme was top of the agenda.

US Attorney-General Eric Holder says they are only allowed to collect information on foot of a court order and when there is a serious terror threat.

He is in Dublin to co-chair the U.S.-EU Justice and Home Affairs Ministerial Meeting and to take part in bilateral meetings with his European Union counterparts.

It comes just days after Edward Snowden leaked top-secret information about the controversial US Prism programme to the media.

Investigation to prosecute Snowden

He has admitted to giving details of the monitoring of phone calls and internet data, from companies such as Google and Facebook, to The Guardian and Washington Post.

Based on the leaked information, both papers disclosed the existence of the Prism system which was set up by America's National Security Agency (NSA) to track customer data directly from ISP servers to fight the threat of terrorism.

The US has launched a criminal investigation to prosecute Mr. Snowden for lifting and exposing the classified material.

Participants at Dublin Castle also discussed counterterrorism and security, cybercrime, cooperation on international criminal matters and issues such as victims' rights.

Acting Deputy Secretary of the U.S. Department of Homeland Security Rand Beers, European Union Vice President and Commissioner for Justice Viviane Reding and European Union Commissioner for Home Affairs Cecilia Malmström are also at the meeting.

Holder also joined the heads of the other delegations in a meeting with victims of violent crimes and their representative groups.

Minister Alan Shatter says Irish and European citizens need this reassurance, while Eric Holder says US security has been damaged as a result of the leaks.