During angry exchanges over the scope and scale of American spies' snooping exposed by the NSA whistlewblower Edward Snowden, Angela Merkel reportedly told Barack Obama his country's conduct was reminiscent of the Stasi.

The German Chancellor had the discussion with her US counterpart in October, shortly after the revelation that her personal mobile phone had been tapped.

According to sources cited by the New York Times: “She told him, ‘This is like the Stasi'," a reference to the intrusive secret police in East Germany, where Merkel grew up.

Download the new Independent Premium app Sharing the full story, not just the headlines

She also apparently questioned the safety of information collected by the US spy agency. The newspaper cites another person familiar with the conversation as saying Merkel told President Obama that it appeared “the NSA clearly couldn’t be trusted with private information, because they let Snowden clean them out.”

The NSA revelations, first reported by The Guardian in June this year, have caused diplomatic friction for the US around the world, and Germany's position as the richest, largest and most important nation in the European Union makes their relations with the US particularly important for Obama.

Snowden is due to testify to a European parliament inquiry on the NSA next month, but the Americans are pressuring the EU to stop the testimony.

American officials said that the German accounts accurately captured the spirit of the conversation, but said the quotes weren't completely accurate.

Video: Tech executives call on Obama for NSA reform