TIANJIN (BLOOMBERG) - The US and China left open the possibility of a summit between their presidents, despite a contentious day of talks in which Beijing outlined a series of demands that Americans showed little willingness to meet.

Foreign Minister Wang Yi reiterated requirements from Beijing in Monday's (July 27) talks in Tianjin with US Deputy Secretary of State Wendy Sherman, namely that the US stop criticising China's political system, drop all sanctions and tariffs, and stay out of Hong Kong, Taiwan and Xinjiang affairs.

Senior Biden administration officials told reporters afterwards that Ms Sherman was focused on setting guardrails on ties, rather than negotiating specific issues. They described the discussions as forthright and professional, even if they were at times tough.

The talks in Tianjin - about 100km east of Beijing - could be the first step towards a meeting between US President Joe Biden and China's Xi Jinping, possibly at a Group of 20 (G-20) summit in October.

"The president continues to believe in face-to-face diplomacy" and expects that will happen "at some point", White House Press Secretary Jen Psaki told reporters when asked whether the differences aired in Tianjin would prevent a Biden-Xi summit.

The challenge facing Washington and Beijing is showing they can get to grips with their disagreements without appearing to domestic audiences to be giving ground. That is proving a tall order given the sour feelings many in the Chinese government still harbour after the trade war that erupted under former US President Donald Trump, and amid a range of disagreements.

"Both sides are trying to seek a complete victory over the other, leaving little room for compromise," said Dr Shi Yinhong, director of Renmin University's Centre on American Studies in Beijing. "It will be a surprise if two countries can find a solution to any of the major issues."

Ms Sherman's trip is part of a broad US diplomatic push in the region, as Mr Biden attempts to extract American forces from Afghanistan and bolster Washington's frayed foreign relationships to better answer the challenges posed by China. Secretary of State Antony Blinken is slated to visit India this week while Secretary of Defence Lloyd Austin is travelling to Singapore, Vietnam and the Philippines.

The US effort to balance criticism and outreach was illustrated in the State Department's summary of the talks. After recounting a litany of complaints - from "the anti-democratic crackdown in Hong Kong" and "the ongoing genocide and crimes against humanity in Xinjiang" to Beijing's conduct in cyberspace and "across the Taiwan Strait" - the department shifted tone to conclude that "the deputy secretary affirmed the importance of cooperation in areas of global interest", including climate change, drug trafficking and weapons proliferation.

But Vice-Foreign Minister Xie Feng, who met with Ms Sherman before Mr Wang, warned that the relationship was "in a stalemate and faces serious difficulties". Mr Xie presented the No. 2 American diplomat with two lists of demands he portrayed as necessary to stabilise ties, including "US wrongdoings that must stop" and "key individual cases that China has concerns with", according to the official Xinhua News Agency.

Among China's demands were ending US efforts to extradite Huawei Chief Financial Officer Meng Wanzhou from Canada. The publication of such requirements makes it more difficult for Mr Biden to grant any of them, as the Democratic president faces domestic pressure to avoid looking soft on Beijing.

Mr Xie's remarks show that the talks were "very tough indeed" and "look like a continuation" of the tense meetings in March in Alaska, said Dr Zhu Feng, a professor of international relations at Nanjing University. "His comments are also aimed at giving the Chinese public confidence that the government will not succumb in the face of heightened pressure from the US side."

Earlier this month, Mr Xi signalled that his government would be more assertive on the world stage, saying at a speech marking the 100th anniversary of the ruling Communist Party that his people "will never allow any foreign forces to bully, coerce and enslave us". Mr Xie used the meeting to take a swipe at Ms Sherman's boss, Mr Blinken, who said earlier this year that Washington's dealings with Beijing were the defining test of the century.

"The Chinese people look at things with eyes wide open," Mr Xie said, according to a statement released by the Foreign Ministry. "They see the competitive, collaborative and adversarial rhetoric as a thinly veiled attempt to contain and suppress China." Ms Sherman's visit follows a series of Biden administration actions challenging China's red lines on what it considers its internal affairs, prompting Beijing to protest and announce fresh sanctions against Americans including former Commerce Secretary Wilbur Ross. Ms Sherman raised US concerns about Beijing's policies in Hong Kong and Xinjiang, and urged the Asian nation to stop its economic coercion of allies, US officials said.

The US and numerous allies this month blamed the hack of Microsoft's Exchange e-mail server software on actors affiliated with the Chinese government and said Beijing's leadership was responsible for an array of "malicious cyber activities".

The US also charged four Chinese nationals linked to the Ministry of State Security with a campaign to hack into computer systems of companies, universities and government entities. China and the US are also at odds over the coronavirus.

The White House said on Thursday China was "stonewalling" a World Health Organization probe into the origins of SARS-CoV-2, including the possibility that it escaped from a lab. Mr Wang, the Chinese foreign minister, dismissed that effort before meeting Ms Sherman, telling Finnish Foreign Minister Pekka Haavisto that "the political virus" seeking to blame Beijing for the pandemic also needed investigation.

Still, Ms Sherman's discussions with Chinese diplomats offered both nations a chance to at least manage their many differences.

"The only positive signal is the two countries agreed to keep in touch," said Dr Shi, the academic. He described that as the "minimum" they could do to prevent a complete falling out.