Prime Minister Shinzo Abe and U.S. President Barack Obama on Thursday underscored their intention to coordinate the response to North Korea’s nuclear test. This will include consulting each other as the U.N. Security Council works on new penalties, a Japanese official said.
The leaders spoke by phone on Thursday morning for 20 minutes. The conversation was initiated by the Japanese side.
Abe told Obama the test posed a “grave security threat,” and that the international community needs to take resolute action. He said doing so would send a strong message to Pyongyang and help prevent further provocation.
Obama concurred, saying North Korea’s claimed hydrogen bomb test was a threat to the region and the international community, the official said. Obama said Washington will take steps to ensure the security of its allies, including Japan.
The pair also agreed to strengthen three-way security cooperation in conjunction with Seoul.
With Japan now serving as one of the 10 nonpermanent members of the Security Council, Abe and Obama also discussed taking the lead in a new resolution to toughen sanctions against North Korea, the official said.
Addressing a full session of the Upper House later Thursday, Abe said Japan may impose unilateral sanctions against the North in addition to any international sanctions.
“We will take decisive measures against North Korea, including consideration of imposing Japan’s own unilateral sanctions,” Abe told the Diet. He also said the government will cooperate with other countries such as the U.S., South Korea, China and Russia to deal with the issue.
Also Thursday, Foreign Minister Fumio Kishida spoke with his American counterpart by phone. U.S. Secretary of State John Kerry emphasized the importance of a unified international response, the State Department said.
It added, he also emphasized the importance of trilateral cooperation with Seoul.
Abe also briefed Obama on the agreement with South Korea to settle grievances over girls and young women who were forced to work at Japanese wartime military brothels.
Obama praised the agreement, saying Abe’s decision to settle the issue had enabled cooperation among Japan, the United States and South Korea on peace and stability.
On Wednesday, North Korea said it had detonated a hydrogen bomb. Overseas seismic monitoring agencies detected a tremor at or near the nation’s known nuclear testing ground.
World leaders moved swiftly to condemn the blast, with the U.N. Security Council meeting to discuss new penalties.
Doubts remain, however, over whether North Korea tested a hydrogen bomb or a regular nuclear device of the kind it is already known to possess. The country previously conducted nuclear tests in 2006, 2009 and 2013. Obama also spoke to South Korean President Park Geun-hye to discuss options.
A South Korean military official said Thursday that the two countries had discussed the deployment of U.S. strategic assets on the Korean Peninsula, but declined to give further details.
After North Korea last tested a nuclear device in 2013, Washington sent a pair of nuclear-capable B-2 stealth bombers on a sortie over South Korea in a show of force. At the time, North Korea responded by threatening a nuclear strike on the United States.
South Korea, technically in a state of war against the North, said it was not considering a nuclear deterrent of its own, despite calls from leaders of the ruling party. The United States is highly unlikely to restore the tactical nuclear missiles it removed from South Korea in 1991, experts said.
The test was a “grave violation” of an August agreement by the two Koreas to ease tension and improve ties, a South Korean national security official, Cho Tae-yong, said in a statement. “Our military is at a state of full readiness, and if North Korea wages provocation, there will be firm punishment.”
The United States is limited in its military response for fear of provoking an unpredictable regime in Pyongyang, said Anthony Cordesman, a defense policy expert at the Washington-based Center for Strategic and International Studies think tank. “Any escalation in this region, any overreaction can easily lead to not only a conflict between South and North Korea, but drag China and the United States and Japan into a confrontation,” Cordesman said.
South Korea also said it would resume propaganda broadcasts by loudspeaker into North Korea from Friday, which is likely to infuriate its rival, in response to Pyongyang’s fourth nuclear test.
The underground explosion also angered China, which was not given prior notice although it is North Korea’s main ally.
A Chinese foreign ministry spokeswoman called for a resumption of so-called six-party talks between the two Koreas, China, the United States, Japan and Russia aimed at curbing North Korea’s nuclear ambitions.