Chinese President Xi Jinping and his U.S. counterpart Donald Trump first agreed in early April to create an action plan by mid-July that would address trade imbalances. Both sides are set to hold their first Comprehensive Economic Dialogue this Wednesday.

The two got the ball rolling in May when China formally agreed to allow imports of U.S. beef, previously banned due to concerns about mad cow disease. In return, Washington pledged to cooperate with Beijing's Belt and Road infrastructure-building initiative.

"The agreements changed the view that the U.S. and China are starting a trade war," said a senior official in China's Commerce Ministry.

Back then, the two nations were on relatively friendly terms since the White House planned to soften its economic stance on China if Beijing would cooperate in resolving the North Korean problem.

Then Pyongyang engaged in a series of missile tests that culminated with an intercontinental ballistic missile that experts fear can reach the continental U.S. Despite that development, Beijing still favors dialogue with Kim Jong Un's regime above harsher sanctions, such as cutting off Chinese petroleum exports.

Trump's patience is seemingly wearing thin. "We've asked [Xi] for some assistance with respect to North Korea," the president said during his visit to France Thursday. "Probably, he could do a little bit more."

With the brief honeymoon over, Washington is readying a much tougher stance, according to a source close to U.S.-China diplomatic channels. And Chinese steel dumping will be brought front and center.

Back in May, both sides agreed to make an effort on the issue, electing to hammer out a concrete plan of action at a later date. China exported nearly 1.2 million tons of steel to America last year. That sum is a third of the peak, but Washington suspects China of pumping in more steel through third-party nations.

Trump is looking at raising tariffs and imposing volume sales caps, which would likely be met with a furious pushback from Beijing during negotiations.