BEIJING — China’s currency weakened past the psychologically important point of 7 to the American dollar for the first time in more than a decade, a move that reflects the growing severity of the trade war with the United States and that could indicate Beijing’s growing desire to find ways to retaliate against President Trump.

The renminbi traded in mainland China on Monday morning at roughly 7.02 to the dollar, compared with about 6.88 late on Friday. A higher number represents a weaker currency. The last time China’s currency was weaker than 7 to the dollar was in 2008, as the financial crisis mounted.

Monday’s move by itself will not change China’s trade relations with the United States. But the shift past 7 renminbi to the dollar could represent a new stage in the economic conflict between the two countries. American officials, including Mr. Trump, have long criticized Beijing for manipulating its currency to help its exporters. Should the currency continue to weaken, the Trump administration will most likely see that as a dramatic retaliation to the White House’s mounting tariffs.

“This can too easily be taken as a trade war devalue to take the pressure off,” said Fraser Howie, an author and former banker who writes about China’s financial system. “To that point, it is the quiet pushback from Beijing.”