Hillary Clinton arrived in Asia on her first overseas trip as US secretary of state today as North Korea prepared to test a ballistic missile which is believed to have sufficient range to reach US territory.

In a move that looked set to heighten rather than defuse tensions between the two countries, the Pyongyang regime announced it would launch a missile, widely though to to be the Taepodong-2, from a base on its east coast.

Before leaving Washington on Sunday, Clinton had said the United States is willing to normalise ties with North Korea and help rebuild its economy if it abandons its nuclear weapons.

On the first day of her trip, which began in Japan today, Clinton said: “My goal is the denuclearisation of North Korea and that means a verifiably complete accounting of whatever programmes they had and the removal of reprocessed plutonium.”

Later, she warned North Korea against following through on a threatened missile launch, saying it would damage its prospects for improved relations with the United States and the world.

Without prompting, she told reporters at a joint news conference with Japanese Foreign Minister Hirofumi Nakasone that such a move would jeopardise the Obama administration’s willingness to work for better ties with Pyongyang.

“The possible missile launch that North Korea is talking about would be very unhelpful in moving our relationship forward,” she said, adding that if Pyongyang wants to end its isolation it also has to fulfill unmet denuclearization pledges made during the Bush administration.

“The decision as to whether North Korea will cooperate in the six-party talks, end provocative language and actions is up to them and we are watching very closely,” Clinton said, referring to the six-nation talks aimed at getting North Korea to abandon nuclear weapons.

“If North Korea abides by the obligations it has already entered into and verifiably and completely eliminates its nuclear program, then there will be a reciprocal response certainly from the United States,” she said. “It is truly up to the North Koreans.”

Analysts and government officials in the region have feared that North Korea may launch a long-range missile to help make its nuclear program a top foreign policy issue for President Barack Obama. North Korea has also threatened a naval clash with South Korea on their disputed western sea border.

“One will come to know later what will be launched,” the North’s state-run news agency, KCNA, said, referring to recent news reports in the region that North Korean engineers have been assembling the 105ft rocket.

By visiting Asia first, Clinton has broken with a long tradition among new secretaries of state of visiting Europe or the Middle East first, a move seen as an acknowledgement of China’s growing status as an economic and military power. Part of her visit to Japan is intended to reassure her hosts that Japan will not be bypassed diplomatically as the Obama attempts to win Chinese co-operation on trade, the environment and regional security.

Clinton will meet families of several Japanese nationals who were kidnapped by North Korean agents in the 1970s and 80s, an issue Tokyo views with more urgency than even the communist state’s nuclear ambitions.

The US angered Japan last year by removing North Korea from its list of states that sponsor terrorism without consulting its ally. Japan has made resolving the abduction a part of any nuclear deal.

Clinton’s arrival in Tokyo came hours after Japan reported its economy had shrunk in the last quarter at its fastest rate since the 1974 oil shock.

“The global economic crisis is the backdrop against which this visit takes place,” she told reporters en route to ¬≠Tokyo, where she will meet the embattled prime minister, Taro Aso and the foreign minister, Hirofumi Nakasone.

In a sign of Aso’s precarious grip on power, Clinton will also hold brief talks with the leader of the main opposition party, Ichiro Ozawa.

A year after her predecessor, Condoleezza Rice, apologised for crimes committed by US military personnel in Japan, Clinton will sign a deal to relocate 8,000 marines from the southern island of Okinawa to the US Pacific territory of Guam.

But she is also expected to reiterate Washington’s commitment to its military alliances with Japan and South Korea, which together host tens of thousands of US troops.

“We have and continue to support a policy of extended deterrence that provides protection as part of our alliance with Japan,” Clinton said last week. “It remains as strong as it has ever been, we are absolutely committed to it.”

While participating in a purification rite and welcoming ceremony at a Shinto shrine to Emperor Meiji today, she said its message of “balance and harmony” would set the tone for the Obama administration’s foreign policy, especially in tough economic times.

“It’s not only a good concept for religious shrines, it’s a good concept for America’s role in the world,” she told about 200 embassy employees afterward. “We need to be looking to create more balance, more harmony. We’re going to reaching out to friends and allies like our hosts here in Japan.”

Clinton, who said last year that “our relationship with China will be the most important bilateral relationship in the world this century,” faces a potentially difficult meeting with Chinese leaders in Beijing.

The US hopes to persuade China, the world’s biggest emitter of greenhouse gases, to support new attempts to cut carbon emissions, and to take a lead in restructuring the global financial system. The US is China’s biggest export market and China is the largest holder of US treasury bonds.

She said human rights would be “part of our agenda” in talks with the Chinese president, Hu Jintao, and the premier, Wen Jiabao, scheduled for the end of the week after stays in Indonesia and South Korea.