US Secretary of State John Kerry arrived Sunday in Japan, the final stop of a four-day Asian tour that has centered on the Korean crisis.
Kerry met Japanese Foreign Minister Fumio Kishida to discuss Korean tensions in an effort to subdue Pyongyang's bellicose saber-rattling and work towards a peaceful solution.
"I think it is really unfortunate that there has been so much focus and attention in the media and elsewhere on the subject of war, when what we really ought to be talking about is the possibility of peace. And I think there are those possibilities," Kerry told a news conference in Tokyo.
After meeting with China's leadership on Saturday, Kerry said China - North Korea's only major ally and trading partner - was "very serious" about resolving the crisis. But he also called on a reluctant Beijing to put more pressure on Pyongyang.
"But you have to begin with a reality, and the reality is that if your policy is denuclearization - and it is theirs as it is ours as it is everybody's except the North's at this moment - if that's your policy, you've got to put some teeth into it," Kerry said.
So far any effort to negotiate with North Korea on its military nuclear program has been unsuccessful, a trend affirmed again on Sunday when Pyongyang rejected South Korean President Park Geun-hye's offer of dialogue.
A spokesman for the North's Committee for the Peaceful Reunification of Korea called the offer "a cunning ploy to hide the South's policy of confrontation and mislead its responsibility for putting the Kaesong Industrial Complex into a crisis."
Last week the North withdrew its 53,000 workers from Kaesong, which South Korea's Yonhap news agency called "the last-remaining symbol of inter-Korean cooperation."
Pyongyang repeatedly issued threats to Japan, South Korea and the US after new UN sanctions were imposed in response to its third underground nuclear bomb test in February.
"We agreed that North Korea should cease provocative speech and behavior and show it is taking concrete action toward denuclearisation," Japan's Kishida said after meeting with Kerry. "We cannot allow North Korea in any way to possess nuclear weapons."
Many have voiced concern over the North's military capabilities, saying its untested mid-range Musudan missiles - recently moved to the country's east coast - could hit targets within an approximate 1550-2,500 mile radius, which includes the US base in Guam.
North Korea will celebrate on Monday the birth of its founder Kim IL Sung, a day often marked with an ostentatious show of military might. It has been suggested that this year the North may use the occasion to launch a missile test.
Kerry said it would be "a huge mistake" if it the North launched a mid-range missile, adding on Sunday that the US would "do what was necessary" to defend Japan and South Korea. But "our choice is to negotiate," Kerry stressed. "Our choice is to move to the table and find a way for the region to have peace."