NANJING, China (Reuters) - Soldiers from China and the United States wrapped up a week of joint disaster relief drills on Saturday, in a display of cooperation against a backdrop of worsening ties between the two countries over trade, the disputed South China Sea and self-ruled Taiwan.

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Relations between the world’s two largest economies have plumbed new depths under U.S. President Donald Trump, who is due to meet Chinese President Xi Jinping at the G20 summit in Argentina starting late this month.

The exercise, held in the eastern Chinese city of Nanjing, comes a week after Chinese Defence Minister Wei Fenghe and top diplomat Yang Jiechi visited Washington, where U.S. officials urged China to halt militarization of the South China Sea.

But there was no sign of those strains as Chinese and U.S. soldiers simulated plucking people from earthquake-destroyed buildings and treating survivors’ injuries at a People’s Liberation Army (PLA) base on the outskirts of Nanjing.

Troops practiced search and rescue in a small mock-up of a devastated urban area post-earthquake, using sniffer dogs and other gear to search for people buried in the fake rubble.

“Only through more contacts, more exchanges and cooperation in areas of common interest can we effectively increase mutual trust and effectively reduce misjudgments,” Qin Weijiang, deputy commander of the PLA’s eastern theater command, told reporters.

“So I think bilateral exchanges can start from humanitarian and disaster relief exchanges and expand to other areas of common interest.”

Robert Brown, Commanding General of the U.S. Army Pacific, said the exchange was “extremely important”.

“Just as our top leaders work towards building a strong working relationship and understanding, we through confidence-building measures like this DME must also at our level build a strong understanding of each other,” he added, referring to Disaster Management Exchange.

This is the 14th time the joint exchange has been held, which last year took place in the United States.

China’s defense ministry has said it hopes the military relationship can become a “stabiliser” for overall ties with the United States.

All the same, Washington and Beijing swapped barbs over trade, investment and regional security at an Asia Pacific Economic Co-operation (APEC) summit on Saturday in Papua New Guinea.

Regular drills and exchanges are helpful to bilateral relations, particularly at a time of increased friction, but they are not going to fundamentally change the direction that ties are headed, said Michael Chase, a specialist in China and Asia-Pacific security at the RAND Corp.

“These exchanges remain important in that respect even if they aren’t going to solve broader problems in the relationship.”