MOSCOW, October 25 (RIA Novosti) – The US National Security Agency monitored the phone calls of 35 world leaders, reveals a classified document from whistleblower Edward Snowden, media reported.

Over 200 numbers, including those of the 35 global leaders, who are not named, were provided by an unnamed US government official, The Guardian reported Thursday citing a confidential memo.

According to the memo, the NSA encourages senior officials in the White House, Department of State, the Pentagon and its other "customer" departments to share their "Rolodexes" to make it possible for the agency to add leading foreign politicians’ phone numbers to their surveillance systems.

The report is likely to add to increasing diplomatic tensions between the United States and its allies, especially after the German chancellor’s accusations. Chancellor Angela Merkel on Wednesday accused the United States of tapping her cell phone.

Snowden, a computer specialist and former contractor for the NSA, was the focus of international attention over the summer after he leaked classified evidence of US government surveillance programs to the media.

He fled to Hong Kong and then to Moscow, where he was granted temporary asylum in Russia in late July despite repeated extradition demands from Washington. He is now living at an undisclosed location in Russia.

A recent report in Le Monde said the NSA had a system in place that alerted it to certain French communications and allowed it to scoop up 70.3 million French phone records in a 30-day period.