President Trump says China and Russia are playing games with their currencies. His own Treasury Department doesn't think so.

Trump said on Twitter on Monday that the two countries are "playing the Currency Devaluation game as the US keeps raising interest rates. Not acceptable!"

Just last Friday, the Treasury Department published a report saying that no US trading partner is manipulating its exchange rate.

The rebuke from Trump added a layer to an escalating trade dispute between the United States and China. It also heightened tensions with Russia, after recently imposed sanctions by the United States and clashes over Syria.

It's not the first time Trump has accused countries of keeping their currencies artificially low to gain unfair advantage in trading with the United States.

Before the presidential election, Trump vowed to label China a currency manipulator on Day 1 of his administration. But he's repeatedly backed away from that promise. In May 2017, in fact, he said China had stopped manipulating its currency, and he personally took the credit.

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The Treasury report issued Friday, a twice-a-year analysis of foreign exchange, kept to criticizing China for the "non-market direction" of its economy and warned of growing risks to its major trading partners and long-term economic outlook.

The Treasury Department also once again called for "further opening of the Chinese economy to US goods and services, as well as reducing the role of state intervention and allowing a greater role for market forces."

A White House spokesperson could not be immediately reached for comment.

Presidents have often used the semiannual reports as a diplomatic tool while engaging with countries that are seen as having exchange rate policies that harm US jobs and economic growth.

Designating a country a currency manipulator doesn't immediately trigger penalties, but is seen by other governments as a provocation.

Since Trump took office, the dollar has weakened substantially against other currencies such as the Chinese yuan. And the ruble has plummeted only in recent weeks because of sanctions against Russia by the United States.

Trump's tweet over a possible currency war comes as central bankers and finance ministers from around the world prepare to gather in Washington for the spring meetings of the International Monetary Fund.