US stocks closed almost flat on Monday, as traders on Wall Street prepared for the Federal Reserve's upcoming interest rate decision.

The Fed has aggressively raised interest rates over the last 18 months to a level not seen for 22 years as it looks to quash inflation still stubbornly above its long-term target of two percent.

But the US central bank is widely expected to hold rates steady following two days of deliberations on Tuesday and Wednesday as policymakers attempt to tackle inflation without tipping the world's largest economy into recession.

The Dow Jones ended the day flat at 34,624, as did the Nasdaq, which closed at 13,710.

The S&P 500 fared slightly better, closing up 0.1 percent at 4,453.

"Nothing happened today, other than a handful of stocks that had news, but the market is waiting for what the Fed's going to do," said Kimberly Forrest from Bokeh Capital Partners.

Among individual firms, Ford, General Motors and Stellantis – the so-called "Big Three" auto manufacturers – all saw their share price slide amid ongoing strike action over pay.

Despite ongoing negotiations, there has been no major breakthrough since the United Auto Workers union launched its first-ever simultaneous strike at plants belonging to the three auto giants late last week. (AFP)