The United States declined to confirm a news report Wednesday that Secretary of State John Kerry has warned against Japanese Prime Minister Shinzo Abe visiting North Korea as it could harm efforts to pressure Pyongyang.

Kerry made the remark during a phone call with Japanese Foreign Minister Fumio Kishida on July 7, saying the recent warming of relations between Japan and the North, if it goes too far, could disrupt cooperation between the U.S., South Korea and Japan in dealing with the North's nuclear and missile programs, according to Japan's Kyodo News agency.

The top American diplomat also asked his Japan counterpart to hold behind-the-scenes consultations with the United States first if Tokyo considers an Abe trip to the North, Kyodo reported, citing an unidentified source close to Japan-U.S. relations.

The reported warning was seen as an expression of U.S. displeasure with Japan easing pressure on North Korea as the two countries have made progress in handling the issue of the North's abduction decades ago of Japanese nationals.

But the State Department declined to confirm the report, only saying that Kerry spoke with his Japanese counterpart and they "discussed the full range of bilateral and regional issues, as well as cooperation that reflects the global nature of our partnership, demonstrating the strength and breadth of our alliance with Japan."

"The United States supports Japanese efforts to resolve the abductions issue in a transparent manner," a State Department spokesperson said. "We are closely coordinating with our allies and partners, including Japan, to take appropriate measures to address the threat to global security posed by the DPRK (North Korea)'s nuclear and ballistic missile programs."

Earlier this month, Japan announced it will lift some of its own sanctions on North Korea in exchange for Pyongyang's promise to reinvestigate the abduction issue. Critics have said the move represents a setback to U.S.-led efforts to pressure Pyongyang to give up its nuclear program.

Japanese officials have talked about the possibility of Abe making a visit to the North in order to help resolve the abduction issue, just as his predecessor, Junichiro Koizumi, traveled to Pyongyang in 2002 and brought home five abducted Japanese nationals.

(Yonhap)