A meeting of top US and Chinese diplomats in Beijing to discuss North Korean nuclear disarmament has got off to a frosty start.
China's Foreign Minister, Wang Yi, criticised America for imposing tariffs on Chinese goods and for accusing Beijing of interfering in US politics.
US Secretary of State Mike Pompeo spoke of fundamental differences.
The US is hoping to get China to support its plan for North Korea's nuclear disarmament.
Mr Pompeo said "significant progress" had been made towards denuclearisation.
He said North Korean leader Kim Jong-un had agreed to allow international inspectors into the Punggye-ri nuclear test site that was dismantled in May.
He also said there were plans for a second summit between Mr Kim and Donald Trump, which the US president mentioned again in a tweet:
The two countries have, however, been in a standoff over what the term denuclearisation means.
The US is pushing for a "final, fully verified denuclearisation" but North Korean Foreign Minister Ri Yong-ho told the UN general assembly in September there was "no way" his country would disarm first as long as tough US sanctions remained against his country.
The trade war between China and the US is however being seen as a barrier to co-operation in the North Korean crisis.
The US has imposed tariffs on virtually half of all Chinese imports into the US and has threatened to target all of its imports.
China has retaliated with its own set of tariffs, and has accused the US of launching the largest trade war in economic history.
Mr Wang said US actions on trade and its support for Taiwan, which China considers part of its own territory, had cast a shadow on the relationship between the two countries.
"The issues that you characterised, we have a fundamental disagreement," Mr Pompeo responded.