A German newspaper is reporting that the US National Security Agency broke the encryption into the United Nation's internal video conferencing.

The weekly Der Spiegel says the NSA, who have been at the centre of revelations by Edward Snowden, broke the encryption last summer.

It is also reporting that the US agency kept tabs on the European Union after it moved into new offices in New York.

Washington has rushed to defend spying programmes following a series of leaks by Snowden, a former IT contractor at the agency.