The UN did not directly comment on allegations on Monday that it had been spied upon, but said it would broach the matter with Washington.

German news magazine Der Spiegel on Sunday reported, citing documents from former National Security Agency (NSA) contractor Edward Snowden, that the NSA cracked the UN's video conferencing system in 2012.

"We're aware of the reports and we intend to be in touch with the relevant authorities on this," UN spokesman Farhan Haq told reporters.

Haq said that longstanding international laws governing diplomatic activities, like the 1961 Vienna Convention, protected the UN, embassies and other international organizations from espionage.

"Therefore member states are expected to act accordingly to protect the inviolability of diplomatic missions," Haq said.

The information at Spiegel's disposal suggested that the NSA - the foreign intelligence agency for the US - had run a bugging program in more than 80 embassies and consulates worldwide called "Special Collection Service". Internal NSA documents quoted in Spiegel's report also suggest that the intelligence officers caught the Chinese secret service eavesdropping on the UN as a by-product of its own infiltration.

The European Union and the UN's nuclear watchdog in Vienna, the International Atomic Energy Agency, were among other institutions targeted by the NSA, according to the report.

The work of the NSA has come under severe international scrutiny in recent months since Snowden turned whistleblower. On August 1, Russia granted temporary asylum to the former NSA contractor, who is wanted on espionage charges in Washington.

msh/ph (AFP, AP, Reuters)