Commerce Department data showed the U.S.-China trade deficit widened 5% to $28.4 billion in June from the month prior and confirmed that Beijing is falling well short of its commitments to buy U.S. goods. Trump has made closing the imbalance a pillar of his economic diplomacy.

"Trump's 'phase one' trade deal with China is failing - badly," Biden said in a statement sent to Reuters.

Ken Farnaso, a spokesman for Trump's re-election campaign, shot back that Biden was "beholden" to Chinese President Xi Jinping and pursued "weak appeasement polices" when he was vice president.

The dueling statements underscored the value both presidential contenders place on staking out a tough-on-China stance ahead of the Nov. 3 election. Many American workers and businesses see China's decades-long rise as coming at their expense.

Under the Phase 1 deal, China pledged to boost purchases of U.S. goods by some $200 billion over 2017 levels, including agricultural and manufactured products, energy and services. Battered by the global coronavirus recession, China is far behind the pace needed to meet its first-year goal of a $77 billion increase.

Biden said the current trade deal is "unenforceable," and "full of vague, weak, and recycled commitments from Beijing," allowing the country to keep "providing harmful subsidies to its state-owned enterprises" and "stealing America's ideas."

Senior U.S. and Chinese officials are set to review the implementation of the Phase 1 trade deal and likely air mutual grievances during an Aug. 15 videoconference, Reuters reported on Tuesday, citing two people familiar with the plans.

China's ambassador to the United States, Cui Tiankai, said on Tuesday that a meeting between the two sides would "be very positive."

By Trevor Hunnicutt