Wall Street stocks opened lower Monday, threatening the S&P 500's nine-day winning streak ahead of a Federal Reserve decision later in the week.

Since a series of rough sessions in early April prompted by President Donald Trump's aggressive tariff policies, stocks have been on the upswing as Trump has pointed to progress towards trade deals and softened or frozen some of his most onerous tariffs.

Analysts said the market could be primed for a pause or pullback after such a strong period.

About 15 minutes into trading, the Dow Jones Industrial Average was down 0.5 percent at 41,113.61.

The broad-based S&P 500 tumbled 0.9 percent to 5,636.71, while the tech-rich Nasdaq Composite index dropped 1.0 percent to 17,806.36.

The Fed on Wednesday is widely expected to extend a recent pause in rate cuts this week as it waits to see how Trump's stop-start tariff rollout affects the health of the world's largest economy.

Most economists expect the tariffs introduced since January to push up prices and cool economic growth -- at least in the short run -- potentially keeping the Fed on hold for longer.