President Barack Obama is in South Korea on the second leg of an Asian tour, where he gave a warning to North Korea against conducting a fourth nuclear test.
In a newspaper interview with South Korea's JoongAng Ilbo, released just before his arrival Friday, Obama said: "If North Korea were to make the mistake of engaging in another nuclear test, it should expect a firm response from the international community."
At a joint news conference later Friday with South Korean President Park Geun-hye, Obama said America's commitment to South Korea will never waiver, and the U.S. and South Korea will stand "shoulder to shoulder" against North Korean provocation.
“The United States and South Korea stand shoulder to shoulder both in the face of Pyongyang's provocations and in our refusal to accept a nuclear North Korea," Obama said. "Threats will get North Korea nothing, other than greater isolation.”
North Korea is already under a long list of sanctions, but the president on Friday suggested more might be necessary.
Obama's visit has been overshadowed by the tragedy of last week's ferry disaster and the loss of more than 300 people listed as dead or missing. Obama expressed condolences to the families of the hundreds of children lost in last week's ferry accident.
Before Obama wrapped up a two-day visit to Japan earlier Friday, the two nations released a joint statement on security and trade. The countries said they share strong concern about China's air defense zone in the East China Sea, but reaffirmed interest in building productive ties with Beijing.
The president is continuing his efforts to ease tensions between South Korea and Japan on issues of history. Many South Koreans believe Japan has not apologized enough for making sex slaves of Korean women and other atrocities committed by its forces while Japan ruled the peninsula from 1910 to 1945.
Obama said a clear accounting is necessary.
“I think that any of us who look back on history what happened to the comfort women here in South Korea for example, have to recognize that this was a terrible, egregious violation of human rights," he said. "Those women were violated in ways that even in the midst of war was shocking."
The U.S. administration hopes to get both sides to move beyond the dispute and focus on the more immediate threat posed by North Korea.
After two days in Seoul, Obama will head to Malaysia, where he will hold talks and attend a state dinner with Prime Minister Najib Razak. He will be the first sitting U.S. president to visit Malaysia since Lyndon Johnson traveled there in 1966.
Obama's last stop will be the Philippines, which is also involved in a territorial standoff with China and has deepened its military cooperation with Washington as a result.
This is Obama's fifth visit to Asia since taking office in 2009. He has promised to make the Pacific region a greater economic, diplomatic and military priority for the United States.