What are the sources of US-China economic tension?

US Treasury Secretary Janet Yellen will arrive in China on Thursday in a bid to inject stability into fraught ties between the world's two biggest economies.

The top US official is expected to meet with Chinese counterparts and representatives from major American companies during a visit that will run through July 9.

Here are the key sources of strain on the US-China economic relationship:

Decoupling and de-risking

Washington and Beijing have butted heads in recent years over a range of hot-button geopolitical issues, fuelling belief among some policymakers that the United States should decouple economically from China.

Many officials in President Joe Biden's administration emphasise the less drastic term "de-risking", or the targeted protection of certain sectors deemed vital to national security.

The Biden administration is considering a programme to restrict certain US outbound investments involving sensitive technology with key national security implications -- an issue that has riled Chinese officials.

"It has very much been received as the US is trying to corner China, trying to stop its rise," Lindsay Gorman, a senior fellow at the German Marshall Fund, told AFP.

"De-risking is essentially the same thing (as decoupling) in their minds," she said.

Chips

Semiconductors represent a key faultline, with China seeking to protect its fledgling domestic industry from mounting export restrictions imposed by the United States.

In March, Beijing launched an investigation into US chipmaker Micron, five months after Washington unveiled sweeping curbs aimed at cutting off China's access to high-end chips, chipmaking equipment and software used to design semiconductors.

Washington has blacklisted many Chinese companies to prevent them from accessing the most advanced chips while pushing its allies to follow suit.

Beijing said Monday that it would slap export controls on two rare metals essential for the manufacture of semiconductors -- gallium and germanium -- citing security concerns.

Debt

Debt will also be on the agenda for Yellen -- both the towering US debt to China, and Beijing's controversial lending to developing countries that are now struggling to repay.

"The open question is whether China is close to reaching agreement with either Sri Lanka or Ghana on the terms of an official debt restructuring," Brad Setser, a former Treasury official and now senior fellow at the Council on Foreign Relations, told AFP.

Yellen's visit represents an opportunity for Washington to coordinate efforts with Beijing in helping the indebted developing nations avoid financial crises.

Tech giants

China's top technology firms have faced increasing global scrutiny in recent years as countries worry about the national security implications of their potential links to the Chinese government.

The United States has warned that using equipment made by Huawei -- China's leading telecommunications firm -- could mean giving access to infrastructure that could be used for state espionage, a claim vehemently denied by Beijing.

Meanwhile, the wildly popular social media platform TikTok, which is owned by Beijing-based ByteDance, has also raised eyebrows in Washington, where policymakers worry about the security of US user data and the potential for the app to be used as a "propaganda tool" for the Chinese Communist Party.

Trade

Tariffs implemented during a trade war launched by former US president Donald Trump are also likely to be discussed during the trip.

Gorman told AFP that she didn't think the United States would be eager to do away with tariffs, and "certainly not unilaterally".

"I don't think anything we've heard from public statements has suggested that that's really on the top of the agenda," she said.

Business environment

The business environment for US firms operating in China has also grown more challenging, with a series of raids and investigations spooking foreign companies.

Recent amendments to China's anti-espionage law -- broadening the definition of spying while banning the transfer of information related to national security -- have caused "a lot of concern for foreign business", said Edward Alden, a senior fellow at the Council on Foreign Relations.

"If there is a resumption of dialogues, then foreign investors become just a little more confident that investing in China is a long-term proposition," he said.

Otherwise, added Alden, if all signals indicate the early stages of decoupling are under way, "the smart thing for foreign investors to do is to look for the exit ramps and figure out how to get out".