US Secretary of State John Kerry Monday headed for tough talks in Beijing seeking to chart a path ahead in turbulent China-US ties roiled by differences over hacking and maritime tensions.

Senior officials will meet in Beijing on Wednesday and Thursday for the sixth Strategic and Economic Dialogue, billed as the main annual meeting between the world's two largest economies.

Kerry departed from Andrews Air Force base, outside of the US capital, just before 1100 GMT for the long trip.

Despite the Obama administration's famous "Asia pivot," already fraught relations have strained further since the Washington in May indicted five Chinese military officers for hacking into US businesses.

Although analysts saw the move as a largely symbolic warning to Beijing since the men are unlikely to appear in a US court, China angrily cancelled key cybersecurity talks due this week.

Alarm is also growing in Washington over Beijing's increasingly assertive moves to stake out its claims to swathes of the South China and East China Seas -- pitting it against regional neighbors, many of whom are strong US allies.

While the US takes no sides in the competing territorial claims, it has accused Beijing of destabilizing acts and urged the Chinese to uphold freedom of navigation in the key waterways.

The top US diplomat for East Asia acknowledged there has been "an uptick" in criticism on each side.

"The trick of course is to manage friction in an effective and constructive way," Assistant Secretary of State Daniel Russel told AFP.

China, on track to overtake the US in the coming years as the world's top global economy, has accused the United States of seeking to rein in its growing clout. Some Chinese officials have also sought to dismiss the US as a country in decline.

Kerry and Treasury Secretary Jacob Lew will lead a large US delegation to meet State Councilor Yang Jiechi and Vice Premier Wang Yang, who will head Beijing's team.

Amid allegations that US businesses are falling prey to unscrupulous Chinese hacking, Washington will push for a resumption of the cybersecurity working group aimed at drawing up rules for using and protecting the Internet.

"There is a growing body of evidence that points to direct Chinese government involvement" in hacking, Russel said.

"Clearly to us that means that the Chinese government has the ability to stop it," he insisted.

- Level playing field -

China's yuan currency will also be a contentious topic.

The US says the yuan remains undervalued despite having appreciated 14 percent since 2010 when Beijing began taking steps to allow it to trade more freely.

While not branding China a currency manipulator which could entail sanctions, Lew last week reiterated the US push for the yuan to trade at a market-determined foreign exchange rate.

"It's fundamentally not fair in terms of trading practices," Lew said.

Climate change and environmental concerns will also be raised.

In an unprecedented move during a visit by Kerry in February, the world's two largest emitters of greenhouse gases agreed to join forces to help combat climate change.

"On the Chinese side, the magnitude of the environmental degradation that is facing China and its citizens has sharpened their minds," Russel said.

Both countries agreed to share information on plans for limiting greenhouse gas emissions ahead of key UN-led talks in Paris in 2015.

Also on the table will be a long-sought bilateral investment treaty, although US officials say it's unlikely to be signed and sealed at this year's talks.

The aim is also to clear the way of any pitfalls ahead of the annual Asia-Pacific Economic Cooperation (APEC) forum, when leaders from more than 20 countries and economies will descend on Beijing in November.