China is going to this week's G-20 summit hoping for a deal to ease a damaging trade war with the United States, Beijing's ambassador to Washington said on Tuesday while warning of dire consequences if U.S. hardliners try to separate the world's two largest economies.

Speaking to Reuters before heading to join Chinese President Xi Jinping's delegation at the Group of 20 summit in Buenos Aires, Cui Tiankai said China and the United States had a shared responsibility to cooperate in the interests of the global economy.

Asked whether he though hardliners in the White House were seeking to separate the closely linked U.S. and Chinese economies, Cui said he did not think it was possible or helpful to do so, adding "I don't know if people really realize the possible consequences — the impact, the negative impact — if there is such a decoupling."