Senior United States administration officials conducted secret discussions with North Korea following the death of Kim Jong Il, according to The Asahi Shimbun.

The report said U.S. military planes shuttled between Guam and Pyongyang on April 7, 2012, and then again from Aug. 18 through Aug. 20 last year. The purpose of the meeting with North Korean officials was to discuss policies in the leadership transition, according to the Japanese daily.

The Shimbun said it believed those aboard the aircraft included: Sydney Seiler, director of Korea at the U.S. National Security Council; and Joseph DeTrani, who formerly led the North Korea department at the U.S. Office of the Director of National Intelligence.

The U.S. did not keep Japan abreast of the talks, “Although the visits had potential implications for Japan,” the newspaper said.

State Department officials told Japan’s Foreign Ministry to stop asking about the meetings, saying such inquiries “would harm bilateral relations” between the U.S. and Japan, according to the Shimbun.

The Shimbun said U.S. officials “unofficially confirmed” another visit in November, 2011, to discuss retrieving the remains of U.S. soldiers killed during the Korean War.

News of the alleged meetings comes as North Korea is carrying out nuclear weapons tests.

President Obama and Japanese Prime Minister Shinzo Abe discussed the nuclear tests Wednesday in a phone call. The two “pledged to work closely together to seek significant action at the United Nations Security Council and to cooperate on measures aimed at impeding North Korea’s nuclear and ballistic missile programs,” according to a White House readout of the call.

Abe also is scheduled to meet with Obama on Friday to hash out “a range of bilateral, regional and global issues,” according the White House.

On Friday, the House passed a resolution by a 412-2 vote condemning North Korea leader Kim Jong Un for performing the reclusive nation’s third nuclear test.

The measure calls on Obama to apply pressure on North Korea through sanctions. It also asks China to stop acting as a courier for technology that can strengthen North Korea’s nuclear program.

The White House has said it will work with the United Nations on sanctions, but GOP lawmakers want Obama to take a harder line with North Korea and question the effectiveness of U.N. sanctions.