Recent U.S. commercial satellite images indicate increased activity around North Korea's nuclear test site, and third-generation dictator Kim Jong Un has said the country's preparation for an ICBM launch is in its "final stage".
Tensions with North Korea have escalated again in the run-up to Tuesday's anniversary of the founding of the North's military amid fears Pyongyang could mark the holiday with a nuclear test in what would be a brazen defiance of the USA and the global community.
Envoys from Japan, the USA and South Korea have gathered in Tokyo to discuss North Korea amid concern it may carry out another nuclear or missile test.
President Donald Trump spoke with the leaders of China and Japan about tensions related to the possibility of North Korea's weapons tests.
The United States could take military action against North Korea if the communist nation attacks a military base in the US or allies, or launches an intercontinental ballistic missile, US Ambassador to the UN Nikki Haley warned Monday.
Haley said the U.S.is working with China to pressure North Korea on the missile and nuclear testing and other issues, including the detention over the weekend of a US citizen, bringing to three the number of Americans now being held there.
The United States has ordered the USS Carl Vinson carrier strike group to sail to waters off the Korean peninsula in response to mounting concern over the North's nuclear and missile tests, and its threats to attack the USA and its Asian allies.
The three envoys also agreed that China has a key role in pressuring North Korea to abandon its missile and nuclear programs.
China is a traditional ally of North Korea and fought on its side in the 1950-53 Korean War. "If there is a partner Trump needs to discuss with foremost over the North Korea problem, it's not Xi Jinping or Shinzo Abe, but the leader of South Korea".
The USS Carl Vinson aircraft carrier and ships in the strike group accompanying it are continuing to move toward the South Korea region, after completing a short naval exercise with Japanese ships in the Philippine Sea. It said the two leaders were committed to "strengthen coordination in achieving the denuclearization of the Korean Peninsula".
South Korea's Defense Ministry has said North Korea appears ready to conduct such "strategic provocations" at any time.
Tuesday marks the founding anniversary of North Korea's armed forces.
"You better believe I'm willing to obliterate North Korea's missile program before I would allow one to hit America", Graham told reporters Monday.
"The status quo in North Korea is also unacceptable", Trump told a meeting with the 15 U.N. Security Council ambassadors, including China and Russian Federation, at the White House.
Japan's Foreign Ministry also announced that China's envoy for North Korea, Wu Dawei, will visit Tokyo later Tuesday for talks with Kanasugi.
Tillerson and U.S. Secretary of Defence Jim Mattis, Director of National Intelligence Dan Coats and General Joseph Dunford, chairman of the Joint Chiefs of Staff, will also hold a rare briefing on North Korea at the White House on Wednesday for the entire U.S. Senate, Senate aides said. The reasons for the detention of Tony Kim, who taught accounting at the Pyongyang University of Science and Technology, weren't immediately clear. No details on why Kim was detained have been released.