Former U.S. President Barack Obama (left) and former German Chancellor Angela Merkel (2009) [EPA Yonhap News]

German intelligence agencies tapped former U.S. President Barack Obama's phone calls from his presidential plane for several years during his tenure, the German weekly newspaper Die Zeit reported on the 4th (local time).

The publication, citing officials from the Federal Intelligence Service (BND), Germany's foreign intelligence agency, stated that the BND exploited a flaw in the encryption system of Air Force One, the U.S. presidential aircraft, to eavesdrop on President Obama. This operation was reportedly halted in 2014.

According to the report, the BND identified approximately 12 frequencies used by the former president for in-flight calls. Only one copy of the recorded conversations was made, which was then reviewed by the BND Director, Deputy Director, and the head of the relevant department before being destroyed.

Die Zeit reported that the intelligence agency was not ordered by the Chancellery to conduct the eavesdropping, and the information obtained was reflected in a "general assessment" of the U.S. position before being reported to the Chancellery.

In 2013, the U.S. and Germany experienced diplomatic friction over the U.S. National Security Agency's (NSA) eavesdropping on then-German Chancellor Angela Merkel. Former Chancellor Merkel criticized the U.S. after former NSA operative Edward Snowden revealed that the NSA had been tapping her phone for over a decade, stating, "There can be no spying among close friends."

Former U.S. President Barack Obama making a phone call on his presidential plane (2012) [EPA Yonhap News] 

The following year, German media reported that the BND had recorded calls made by then-U.S. Secretary of State John Kerry and his predecessor, Hillary Clinton. The BND was reportedly monitoring terrorism suspects in the Middle East and inadvertently intercepted their conversations.

At the time, the German Chancellery ordered a halt to such practices and instructed that accidentally recorded conversations be immediately destroyed. However, Die Zeit reported that the Chancellery was unaware of the BND's eavesdropping on former President Obama at that time.

Holger Stark, a Die Zeit journalist who recently published a book on these events, claimed that the BND also tapped the communications of Hillary Clinton and the U.S. military. However, he stated that it was unclear when the eavesdropping on former President Obama began, or if his predecessor, George W. Bush, was also targeted. The BND stated, "We generally do not make public statements on matters related to intelligence activities."