Washington (CNN) -- Affirming strong ties in a time of challenges, President Barack Obama and visiting Japanese Prime Minister Yoshihiko Noda on Monday hailed an agreement to move U.S. Marines from Okinawa and expressed solidarity against North Korea's nuclear weapons program.
The two leaders held bilateral talks at the White House and then labeled U.S.-Japan ties an essential alliance for both countries and the Asia-Pacific region.
They confirmed that much of their discussion Monday focused on North Korea, which has signaled plans to conduct a nuclear test after its recent failed missile launch. The United States and Japan lead an international effort to get Pyongyang to give up its nuclear arms ambitions.
"There is a great possibility they will conduct a nuclear test," Noda said of North Korea, adding that the issue deepened the U.S.-Japan alliance through their cooperative efforts.
Obama also noted how consultations between his government and Japan around the failed missile launch earlier this month showed the importance of the alliance.
"We continue our close consultations on the provocative actions of North Korea, which are a sign of weakness and not strength and only serve to deepen Pyongyang's isolation," Obama said
Noda is Japan's sixth prime minister in five years, a reflection of political volatility amid an economic slowdown worsened by the global recession.
He came to power in September as the Pacific power continued struggling with the effects of last year's earthquake and tsunami that killed at least 16,000 people and triggered a nuclear power plant meltdown.
In his remarks at a joint news conference, Noda thanked the United States for its support in the aftermath of the disaster and said the Japan-U.S. alliance "has reached new heights."
Last week, the two governments addressed a thorny issue of recent years with a plan for the United States to relocate about half of its 19,000 Marines based on Okinawa to other places in the Pacific region.
While the relocation faces some opposition in Congress and Japan, the announcement of an agreement signaled a desire by the countries to work together on a way forward in bilateral relations.
Obama praised Noda for his role in addressing the longstanding problem of opposition on Okinawa to the U.S. military presence.
"The realignment approach being taken is consistent with the security interests of both Japan and the United States," Obama said, noting it fit his strategy announced in Australia last year of broadening the U.S. military presence in the region to offset China's growing dominance.
Another topic Monday was Japan's possible membership in the Trans-Pacific Partnership, a trade alliance that is part of Obama's strategy to increase U.S. exports and influence in the Asia-Pacific region.
Participants so far in negotiations on the partnership include Australia, Brunei, Chile, Malaysia, New Zealand, Peru, Singapore, Vietnam and the United States.
Canada and Mexico also have expressed interest in joining, and Obama said U.S. and Japanese officials will consult on possible Japanese participation.
Last month, Noda issued a sobering and reflective assessment of his country's recovery a year after the 9.0-magnitude earthquake, tsunami and nuclear meltdown at the Fukushima Daiichi plant.
The resulting release of radioactivity forced residents of several towns near the plant to flee their homes, and a 20-kilometer (12.4-mile) zone around the plant remains closed to the public.
Only two of Japan's 53 nuclear reactors remain in operation, with others taken offline for routine maintenance and then idled.
The strain on the grid with summer approaching is raising concern in corporate Japan, which fears it won't have enough power to run production lines in the country.
"In case there is a short-term supply and demand gap of energy, it could cause downward pressure on the economy. We must avoid that," Noda told CNN last month.
The prime minister faces not just the nuclear cleanup and disaster reconstruction, but an economy facing intense pressure.
Japan's currency, the yen, remains at historic highs versus the U.S. dollar.
A high yen makes it more expensive for Japanese corporations to make a profit when the funds are repatriated, dragging down corporate profits, domestic investment and employment.
Japan's debt-to-gross domestic product ratio is highest among developed nations, topping 200%. The country is also aging at an unprecedented rate. By the year 2050, the government projects, 40% of the population will be older than 65, straining public funds while relying on a dwindling tax base.
The centerpiece of the prime minister's economic policy has been the doubling of the country's sales tax, from the current 5% to 10% by October 2015.
The plan remains unpopular with voters, but the prime minister has repeatedly endorsed fiscal responsibility in the wake of the shrinking economy.
CNN's Kyung Lah and Tom Cohen contributed to this report.