U.S. President Joe Biden has arrived in Japan on the second leg of his first trip to Asia as president.

Biden will have a busy two days. On Monday, he is set to meet with Prime Minister Fumio Kishida and Emperor Naruhito, as well as promote a U.S.-led, multination trade initiative. On Tuesday, he will join the Indian, Australian and Japanese leaders for a summit of the Quad group.

Biden landed at Yokota Air Base outside Tokyo after spending two days in South Korea, a trip underlining U.S. economic commitment to the region. U.S. officials could only speculate whether North Korea might test a nuclear-capable missile or bomb while the U.S. leader visits the region after ignoring Washington's attempt at outreach.

North Korean dictator Kim Jung Un did not detonate a test while Biden was in neighboring South Korea, but U.S. officials remain in the dark on what yet might happen.

Jake Sullivan, Biden's national security adviser, told reporters en route to Tokyo, "Anytime people start speculating on what North Korea might or might not do, they tend to have their expectations confounded one way or another."

"We were prepared for any contingency while we were in Korea," Sullivan said. "We're prepared for any contingency while we're in Japan, and we will stay very closely lashed up with (South Korea) and Japan on this."

"And if North Korea acts, we'll be prepared to respond," he said. "If North Korea doesn't act, North Korea has the opportunity, as we've said repeatedly, to come to the table and start negotiating" over dismantling its nuclear arsenal.

Meantime, Biden and his aides are promoting the long-term stability and growth of the American economy, the world's largest, in the face of a four-decade-high surge in consumer prices in the United States and supply chain disruptions in world trade.

Sullivan said, "The fact that the United States will grow faster than China (the world's No. 2 economy) this year, for the first time since 1976, is a quite striking example of how countries in this region should be looking at the question of trends and trajectories."

He echoed Biden's oft-repeated sentiment, saying, 'It's never a good bet to bet against the United States. And actually, we think a lot of countries in this region are recognizing that fact."

He said the multinational trade initiative Biden is unveiling Monday "will be strong evidence that countries do want to bet on the United States, do want to be part of an economic arrangement with the United States, where we're setting rules together, we're building diverse and resilient supply chains together, that American innovation is at the heart and American infrastructure investment is at the heart of the economic strategy of a lot of these countries."

Biden's promotion of the U.S. economy comes as China is experiencing significant economic disruption due to COVID-19 outbreaks.

On Tuesday, Biden is meeting with Indian Prime Minister Narendra Modi, newly elected Australian leader Anthony Albanese and Kishida at a summit of the Quad group.

Sullivan said international "food security" will be one topic up for discussion, with Modi's decision a week ago blocking export of Indian-produced wheat on top of Russia blocking Ukrainian wheat exports to the world market during the ongoing war between the two countries.