The US Wall Street market showed a decline after recording positive gains for two consecutive days.
The major indexes plunged due to the five-day Israeli-Iran conflict and the possibility of US military involvement in joining Israel in fighting against Tehran.
The S&P 500 index fell 0.84%, the Dow Jones dropped 0.70%, while the technology-focused Nasdaq slid 0.91%.
US President Donald Trump is considering several actions, including a possible attack on Iran, after discussing with top advisers in the White House Situation Room yesterday.
Trump also demanded unconditional surrender from Iran and warned that US patience was running out and insisted that Iran sign the nuclear deal and not have nuclear weapons.
Trump also ordered the deployment of additional aircraft carriers and strategic bombers in the region as a precautionary measure, although the US has not officially participated in the Israeli attack on Iran.
Israel hopes the US will help attack Iran's underground nuclear facilities such as the Fordow facility, which requires a special bomb that only the US has.
In other developments, the Federal Reserve (Fed) central bank has held a two-day FOMC meeting starting yesterday and tomorrow at 2:00 am local time to announce interest rate policy.
However, the Fed is expected to keep interest rates around 4.5% at the end of Wednesday's meeting due to stronger labor market and inflation data in May showing growth.
Investors are now worried about escalating Israeli-Iranian tensions following the deployment of US fighter jets to the Middle East.
US stock market trading volume recorded $15.71 billion compared to an average of $17.98 billion over the full 20 trading days.
