U.S. President Donald Trump on Friday dug in on his criticism of the Federal Reserve’s policy on raising interest rates, saying it takes away from the United States’ “big competitive edge,” and lamented the strength of the U.S. dollar.

Trump, in posts on Twitter, also accused the European Union and China of manipulating their currencies.

“China, the European Union and others have been manipulating their currencies and interest rates lower, while the U.S. is raising rates while the dollars gets stronger and stronger with each passing day – taking away our big competitive edge,” Trump wrote. “As usual, not a level playing field.”

After his posts, the U.S. dollar extended losses against the European Union’s euro, the Chinese yuan and Japanese yen.

Representatives for the Fed could not immediately be reached for comment.

Trump had already criticized the Fed’s interest rate policy in an interview on CNBC on Thursday, saying he was concerned higher rates could impact the U.S. economy.

Most economists believe the current economic climate, with the nation’s unemployment at historic lows and inflation at the Fed’s 2 percent target, justify recent interest rate rises and a strong U.S. dollar.

The issue also ties into the Trump administration’s current trade battles with China, Europe and others, as a strong currency tends to make a country’s exports more expensive, hurting exporters.