U.S. President Barack Obama says the United States and South Korea are as "united as ever," while North Korea is "more isolated than ever."
Speaking at the White House Tuesday alongside South Korean President Park Geun-hye, President Obama says the days when North Korea could issue a threat and elicit concessions are "over."
The news conference followed a meeting between the two leaders that included talks on North Korea and its recent wave of nuclear threats.
White House officials said the meeting was meant to reaffirm the United States' commitment to the defense of South Korea. President Obama said the two leaders agreed to continue implemenation of historic trade agreement as well as clean energy partnerships and security collaboration
President Park is in the U.S. for a five-day visit, which she began Monday at the United Nations in New York. U.N. Secretary-General Ban Ki-moon praised the South Korean leader for what he called her "firm, but measured" response to North Korea's provocations.
North Korea has gradually reduced the intensity of its rhetoric, following weeks of threats of nuclear and conventional attacks against the U.S. and South Korea.
On Monday, U.S. officials said they believe North Korea has removed two mid-range missiles from imminent-launch status, in an apparent further easing of tensions on the Korean peninsula.
Washington had for weeks warned North Korea could launch the untested Musudan missiles, which have a range of up to 3,500 kilometers and could reach several U.S. targets in the region.
But speaking anonymously late Monday, Washington defense officials said Pyongyang recently moved the two missiles from a launch site on the country's east coast. South Korean media have also reported the move.
Daniel Russel, the White House Senior Director for Asian Affairs, says it is premature to celebrate the development as "good news," warning that U.S. officials cannot rule out a test.
In an interview with VOA, Mark Fitzpatrick, the director of the Non-Proliferation and Disarmament Program at the International Institute for Strategic Studies, agreed the threats may not be gone just yet.
"After several weeks of ratcheting up the pressure with horrendous statements and threats and moving the missiles to a launch site and doing other things, North Korea is now taking a positive step of moving those missiles. But on the other hand, it is still engaged in a very fierce rhetorical and economic conflict with South Korea."
At a dinner event for Korean Americans held in Washington Monday night, President Park said her government is responding to North Korean threats in a "firm and calm manner" by coordinating with the international community, including both the United States and China. She said South Korea is open to establishing a cooperative relationship with its northern neighbor.
"If North Korea stops its provocations and moves toward a right path embraced by the international community, even at this moment we will open the way for the prosperity of the two Koreas through an inter-Korean trust building process."
The South Korean leader is also scheduled to address a joint meeting of Congress on Wednesday. President Park, who is heading a delegation of more than 50 South Korean business leaders, will stop in Los Angeles Thursday to meet with Korean entrepreneurs.
Pyongyang has been upset at United Nations sanctions that were expanded in response to its latest nuclear test. It also responded angrily to annual joint military exercises between the U.S. and South Korea.
"Our government is responding to North Korean threats in a firm and calm manner by maintaining a strong deterrence with enhanced coordination with the international community, including the United States and China."