President Barack Obama told Japan's politically weakened prime minister he would nurture an already rock-solid alliance with Tokyo and called the relationship the "cornerstone of security in East Asia."

"Obviously, the friendship between the United States and Japan is extraordinarily important to our country," Obama said in a meeting in the Oval Office with Japanese Prime Minister Taro Aso.

"It's one that my administration wants to strengthen," Obama said, as he sat next to Aso for talks to cover the global economy, North Korea and Afghanistan.

In office for only a month, Obama bestowed on Aso the prestige of being the first foreign leader to visit the White House, despite uncertainty in Japan about whether Aso's time in office may be limited.

After a series of flip-flops and gaffes by his government, some in Aso's own Liberal Democratic Party have called for him to be replaced and a poll released this week showed almost four out of five Japanese voters want him to quit within months.

While emphasizing the importance of the bonds between the two countries, the White House did little to put a big spotlight on the meeting, perhaps in view of Aso's precarious political position.

The meeting took place hours before Obama was to give a major, nationally televised speech in which he will discuss the newly passed $787 billion economic stimulus plan and other efforts to rescue the U.S. economy from its freefall.

"Japan has been a great partner on issues ranging from climate change to Afghanistan. We're going to have a very busy session," Obama told reporters.

Speaking in English, Aso said he was "very honored" by invitation to visit and said the countries would "work together hand in hand" on issues like the economic crisis.

ANXIETY ABOUT THE RELATIONSHIP

"This meeting is not about the individuals so much as it is about the relationship between the countries," said Ralph Cossa, head of the Pacific Forum think tank at the Center for Strategic and International Studies.

Cossa said that despite the staunch friendship with the United States, there has been some anxiety in Japan over moves in the final years of the Bush administration to engage North Korea as part of an effort to persuade Pyongyang to dismantle its nuclear weapons program.

Obama's campaign promise of broad engagement with foes like North Korea unsettled Tokyo. Separate concerns center on fears that the Obama administration may be inclined to pursue more protectionist trade policies.

But the Obama administration has sought to ease any concerns about Japan's place in U.S. foreign policy.

U.S. Secretary of State Hillary Clinton made Tokyo the first stop on her Asian tour last week and bluntly talked of a possible power struggle in Pyongyang. She said that situation made it all the more urgent to end North Korea's nuclear weapons program.

On Tuesday, North Korea said it was preparing to launch a satellite on one of its rockets, which analysts have said would actually be the test-firing of a long-range missile designed to strike U.S. territory. The news weighed on South Korean financial markets.

Shared worries about the economy were also expected to be a huge topic. U.S. stock prices tumbled on on Monday to a 12-year low, although they rebounded on Tuesday amid bargain-hunting.

Japanese media have speculated that the need to find buyers for a raft of new U.S. Treasury bonds to fund the massive U.S. economic stimulus package may be one reason behind Obama's charm offensive. Japan is the second-largest holder of U.S. government bonds after China.

But a Japanese official said he did not expect the issue to be on the agenda and that Tokyo sees "no particular problem" in the bond market at this time.

Japan is suffering economic woes of its own. Plummeting exports have led to the worst contraction since the 1970s in the final quarter of 2008.