WASHINGTON — The Trump administration, which has been on the verge of a trade war with China, opted on Friday not to label the country a currency manipulator, breaking a key campaign promise by President Trump to punish a government he has called the “greatest currency manipulators ever.”

The Treasury Department, in its biannual currency exchange report, scolded China for its lack of progress in reducing the bilateral trade deficit with the United States, but did not find that it was improperly devaluing its currency, known as the renminbi.

“Treasury is strongly concerned by the lack of progress by China in correcting the bilateral trade imbalance and urges China to create a more level and reciprocal playing field for American workers and firms,” the report said.

It was the third time since Mr. Trump assumed the presidency that the Treasury Department opted not to accuse China of improper meddling. China has long maintained a strong grip on the value of its currency and, for years, weakened it compared with the dollar to make Chinese products cheaper to sell in the United States and other countries. More recently, China has made a big show of gradually loosening its grip, an effort meant to mollify critics like Mr. Trump and experts who have long urged Beijing to let markets fix financial problems in the world’s second-largest economy.