China has lodged "stern representations" with the United States over a US navy vessel sailing through the disputed South China Sea, as US officials joined trade talks in Beijing to seek a de-escalation in the Sino-US trade war.

Lu Kang, spokesman for China's foreign ministry, said on Monday that Chinese military aircraft and naval vessels were dispatched to identify the US vessel and warn it to leave the area near the disputed Paracel Islands in the South China Sea, claimed by China.

"We urge the United States to immediately cease this kind of provocation," he said, adding that China has lodged "stern complaints with the US" over the move.

The warship, he said, had violated Chinese and international law, infringed on Chinese sovereignty, and undermined peace and stability.

Rachel McMarr, spokeswoman for the US Pacific Fleet, said the USS McCampbell carried out a "freedom of navigation" operation, sailing within 12 nautical miles of the Paracel Island chain, "to challenge excessive maritime claims".

The operation was not about any one country or to make a political statement, McMarr said in a statement to the Reuters news agency.

Asked about the timing of the operation during trade talks, Lu said resolving issues would benefit the two countries and the world.

The working-level talks held at the Chinese Commerce Ministry were the first round of face-to-face discussions since both sides agreed to a 90-day truce in a trade war that has roiled international markets.

"Both sides have the responsibility to create the necessary positive atmosphere for this," he said.

Trade war

US President Donald Trump and Chinese President Xi Jinping in December agreed to pause a spiralling trade dispute of tit-for-tat import tariffs on hundreds of billions of dollars worth of goods.

Trump has imposed tariffs to pressure Beijing to change its practices on issues ranging from corporate espionage to market access and industrial subsidies. China has retaliated with tariffs of its own.

Pauline Loong, head of the Hong Kong-based think-tank, Asia Analytica, told Al Jazeera that China "wants an agreement to end the trade dispute as soon as possible".

"For the Trump administration, the question is what will happen to its voter base if the trade war drags on for too long. But for China, it's very serious," she said.

"This trade fight couldn't have come at a worse time for China. Its economy is in trouble, not just cyclically, but structurally. It's got a debt mountain that is three times that of GDP, non-performing loans are up, and all the banks are in serious trouble - worrying about what is going to happen next."

However, Loong said she did not expect an agreement until the end of the truce in March.

"Both sides are going to want to squeeze everything they can during this time to get the best out of the time that is remaining. So I do not expect anything dramatic to be announced before March," she said.

There are growing concerns that the trade war could escalate into a broader conflict between the US and China, as top Trump administration officials have attacked China on issues ranging from alleged human rights abuses to influence operations in the US.

The two countries are also at odds over regional security, including Washington's overtures to the self-ruled island of Taiwan, which Beijing claims as its own.

China and the US have in the past traded barbs over what Washington says is Beijing's militarisation of the South China Sea, by building military installations on artificial islands and reefs.

China claims almost all of the strategic South China Sea and frequently attacks the US and its allies for carrying out freedom of navigation naval operations near the Chinese-occupied islands.

Vietnam, the Philippines, Brunei, Malaysia, Indonesia and Taiwan have competing claims in the region.

China defends its construction as necessary for self-defence and says Washington is responsible for ratcheting up tensions in the region by sending warships and military planes close to islands Beijing claims.