The S&P 500 Index fell Monday to start the week as falling oil prices and Russia's ongoing war with Ukraine weighed on earlier gains. Investors also looked ahead to the Federal Reserve's next monetary policy decision later this week amid surging inflation. The Dow Jones Industrial Average closed at a positive flatline, while the Nasdaq Composite sunk over 260 points amid a broad tech sell-off.

Market participants expect the Fed to raise interest rates for the first time since 2018, while Fed Chair Jerome Powell telling Congress earlier this month that he would support a 25 basis point rate hike following the March meeting.

Here's how the market settled to start the week:

S&P 500 Index (SPY  ): -0.74% or -31.25 points to 4,173.06

Dow Jones Industrial Average (DIA  ): +0.00% or +0.59 points to 32,944.78

Nasdaq Composite Index (QQQ  ): -2.04% or -262.59 points to 12,581.22

Oil prices dip below $100 per barrel, slightly recover:

Oil prices fell by more than 8% on Monday, tumbling below $100 per barrel, as new pandmeic restrictions in China weighed on demand outlooks.

U.S. benchmark West Texas Intermediate (USO  ) sunk by as much as 8.75% to trade at $99.76 per barrel, at its lows for the day. Meanwhile, international benchmark Brent Crude (BNO  ) lost 8% to trade at $103.68 per barrel.

Despite the earlier losses, oil prices slightly recovered in afternoon trade. West Texas Intermediate settled 5.78% lower on Monday at $103.01 per barrel, while Brent finished 5.1% lower at $106.90 per barrel.

China issues fresh COVID restrictions in Shenzhen amid local COVID outbreak:

China has issued new pandemic restrictions in Shenzhen, the biggest city in the manufacturing hub of guangdong province, as the city reports more than 400 confirmed COVID-19 cases since late February--the nation's biggest outbreak since it first issued COVID restrictions in 2020.

City officials told all businesses not involved with essential public services to suspend production or have employees work from home for a week starting Monday, according to multiple reports, as the city works to contain its outbreak. Shenzhen has also halted public transportation and began a third city-wide round of testing.

Notably, Foxconn, a major assembler of Apple's (AAPL  ) iPhone, announced Monday it is pausing operations in Shenzhen in compliance with the city's public health mandate.

Here's how benchmarks started trading soon after open:

S&P 500 Index: +0.37% or +15.58 points to 4,219.90

Dow Jones Industrial Average: +0.71% or +234.83 points to 32,179.02

Nasdaq Composite Index: -0.25% or -32.71 points to 12,811.10