The South Korean government has requested a reply from the United States on whether South Korea was one of the 35 countries whose leaders were reportedly wiretapped by the U.S. intelligence agency, an official said Sunday.

“We are checking with the U.S. side for verification,” the government official said. “The government is closely following the issue and is determined to respond strictly.”

The official said Seoul has not yet received any answer from the U.S.

The British daily the Guardian had previously reported that the U.S. National Security Agency wiretapped the phones of at least 35 leaders of foreign countries, referring to the intelligence agency‘s document, written in 2006.

South Korea previously made a similar request to the U.S. amid the media revelation that the U.S. eavesdropped on the embassies of foreign countries in the U.S.

“At that time, the U.S. had said that it gravely understands the concerns of the ally and is reviewing the country’s intelligence activities in general,” the official also noted. (Yonhap News)