USD traded little changed against its major rivals in the European session on Tuesday amid heightened concerns about possible delays to Biden's coronavirus relief plan.

The U.S. Dollar Index (DXY), measuring the U.S. currency's value relative to a basket of foreign currencies, edged down 0.09% to 90.31.

Biden's $1.9 trillion coronavirus relief bill faced obstacles in the Senate, as several Republican lawmakers expressed opposition about the size of the proposed measures. As Democrats, who hold only a slim majority in the Senate, are still trying to convince Republicans of the need for more stimulus, questions raised over when and in what volume a package will be approved. President Joe Biden stated on Monday that he was "open to negotiating" terms of his coronavirus relief plan.

In addition, market participants are awaiting the beginning of a two-day policy meeting of the U.S. Federal Reserve, which is to kick off later today. The Fed is not expected to make any changes to its policy stance at the meeting. Investors wait for an update from the Bank's governor Jerome Powell on the economic outlook.