Spot gold was steady at $1,340.51 as of 0126 GMT.
U.S. gold futures were almost unchanged at $1,343 an ounce.
The Fed, facing fresh demands by U.S. President Donald Trump to cut interest rates, begins a two-day meeting later on Tuesday, with expectations running high the central bank is poised to cut interest rates this year.
However, the central bank is expected to leave borrowing costs unchanged this time but possibly lay the groundwork for a rate cut later this year.
The European Central Bank is also holding a forum in Portugal this week, with the Bank of Japan set to hold its policy meeting later in the week.
Investor caution ahead of the Fed’s interest rate meeting capped Asian stocks on Tuesday, while crude oil prices retreated as global growth worries overshadowed supply concerns stemming from recent Middle East tensions.
U.S. Treasury yields fell on Monday, weighed down by softer-than-expected U.S. economic data and persistent pressure from the trade conflict with China.
The dollar index against a basket of six major currencies stood little changed after pulling back from a two-week high on the decline in Treasury yields.
Newmont Goldcorp said on Monday it had resumed shipping concentrate from the Peñasquito gold mine in Mexico after a blockade by a trucking contractor and some members of the Cedros community was lifted.
Switzerland’s Metalor, one of the world’s biggest gold refineries, said on Monday it would work only with gold from large industrial mines in order to reduce the risk of illegality in its supply chain.