Japan booked a trade surplus for a second month in a row, despite the carnage of its worst post-war catastrophe, which claimed more than 20,000 lives, destroyed entire towns and wreaked widespread economic havoc.

But even with the relatively hopeful trade data, analysts warned more turbulence could lie ahead because of uncertainty over the US and eurozone economies as well as the rising yen, which makes Japan's export goods less competitive abroad.

Japan's exports in July were down 3.3 percent from a year earlier, at 5.78 trillion yen ($75.4 billion), a figure that beat market expectations of a 4.4-percent fall, the finance ministry said.

Compared to June, exports grew a seasonally adjusted 0.8 percent, the third straight month of expansion.

Japan managed to book a trade surplus of 72.5 billion yen -- a figure 90.8 percent lower than the same month last year, and nearly matching the market forecast of a 70.1 billion yen surplus.

Meanwhile, imports grew 9.9 percent to 5.71 trillion yen on rising energy prices, the ministry said.

"For the immediate term, we are seeing a recovery," said Satoshi Osanai, an economist at the Daiwa Institute of Research.

Export-oriented manufacturers have rebounded since the March 11 disaster devastated Japan's northeastern coast, destroying factories and infrastructure and disrupting industrial supply chains.

Economists have generally expected Asia's second largest economy to continue to strengthen for now, fuelled by quake reconstruction demand.

Gross domestic product data on Monday showed Japan's economy shrank by a smaller-than-expected annualised 1.3 percent in the April-June quarter, fuelling hopes that it will grow again in July-September.

But the trade outlook worried some analysts, who said the persistent strength of the yen, a safe-haven currency in times of crisis, and uncertainty in key exports markets spell risks for Japan.

As the yen recently neared a post-war high against the dollar, forcing the government to intervene in markets, Japan's major manufacturers have threatened to move their factories overseas to mitigate the effect of the rocketing unit.

US-bound exports fell 8.2 percent in July, the fifth straight monthly drop, with auto and auto-parts down 14.4 percent and 11.0 percent respectively. Asia-bound exports fell 2.7 percent but exports to EU nations rose 6.0 percent.

Japan could face a slowdown at year's end as global semiconductor and auto demand softens, said Daiwa's Osanai.

"We have concerns once the current recovery starts to lose steam. Broadly speaking, it's about the global economy and foreign exchange," he said.

Norio Miyagawa, senior economist at Mizuho Research and Consulting, said the latest trade data "could be signalling that the nation's exports have started to slow due to weaker growth in overseas economies.

"Though we need to check more data in the coming months, the decline in exports volume is a bit worrisome," he told Dow Jones Newswires.

Xi Jinping made the comments at a roundtable of American and Chinese business leaders hosted by Joe Biden, who is trying to shore up the reputation of his country's economy on his five-day trip after a debt crisis.

China's Vice President Xi, who is widely expected to be named as the country's next leader in 2012, was speaking ahead of planned talks between Biden and Chinese President Hu Jintao later Friday.

"The US economy is highly resilient and has a strong capacity of self repair. We believe that the US economy will achieve even better development as it rises to challenges," said Xi.

"We hope that the business people of the two countries will bring forth confidence and work hard to turn challenges into opportunities and embrace change and innovation."

Xi also said that the Chinese economy would not suffer a hard landing, and called on the United States to ease trade restrictions and provide for fair treatment of Chinese firms.

The United States and China "should not politicise or sensationalise trade issues", he added.

Biden's talks with Hu and Premier Wen Jiabao later Friday will take place against a backdrop of intense criticism in China, the largest foreign holder of US debt, over Washington's handling of the debt crisis.

Xi's conciliatory comments contrast with the attitude taken by Chinese state media in recent weeks, which has accused US leaders of acting irresponsibly after the world's largest economy came close to a disastrous default on its debts earlier this month and suffered a historic credit rating downgrade.

In a meeting Thursday, Biden told his Chinese counterpart he was "absolutely confident that the economic stability of the world rests in no small part on cooperation between the United States and China".

"It affects every country from your neighbour to the north, to Argentina in the southern tip of South America. It is the key, in my view, to global economic stability," he added.

Biden's trip is aimed partly at building ties with the likely next leader of the world's second-biggest economy, who remains virtually unknown in US policy circles.

It comes amid growing concern about China's human rights record in the United States, which this week appealed to Beijing to free prominent rights lawyer Gao Zhisheng. US officials said he had raised the issue with Xi.

Gao, who defended some of China's most vulnerable people including Christians and coal miners, was placed under house arrest in 2006 and has not been heard of since last year.

But the main focus of the China visit -- Biden's first as vice president -- will likely be on Beijing's concerns over the safety of its US investments.

China, which held around $1.17 trillion in US Treasury bonds at the end of June, watched nervously as a political impasse brought Washington close to default this month and Standard & Poor's downgraded the country's credit rating.

Biden is also expected to suggest that China should focus on its own economic reforms, such as letting its currency appreciate and shifting from a reliance on exports to an economy based on consumption.