CNBC Daily Open: Markets take a beating despite Trump's reassurances

South Korea's Kospi recorded its worst day on record, plunging 12% on Wednesday. Asian markets saw losses across the board, while U.S. markets also fell. The S&P 500 slipped about 0.94%, while the Dow lost 0.83%. At one point, the Dow fell more than 1,200 points. The Nasdaq Composite closed down 1.02%.

Gulf nations said their weapons stockpiles are sufficient as Iran continued drone and missile strikes on the fifth day of its war with Israel and the U.S. Executives from U.S. defense contractors Lockheed Martin and RTX, the parent company of Raytheon, are expected to meet White House officials Friday to discuss accelerating weapons production.

Global central banks are facing fresh tests as the Middle East conflict widens, amid fears of an oil shock and renewed inflation risks complicating policymakers' calculus for shoring up growth.

China's factory activity faltered in February as manufacturers paused production and cargo shipment to celebrate an extended holiday. The official manufacturing purchasing managers index fell to 49 in February, according to the National Bureau of Statistics, missing economists' forecast for 49.1. 

China is set to kick off its "Two Sessions" meeting. What will be the key announcements?

China's top policymakers are due to release growth targets and stimulus plans for the year at an annual parliamentary meeting that kicks off Wednesday.

The gathering, dubbed the "Two Sessions," consists of a consultative congress that will start later in the day, and a National People's Congress due to open Thursday. 

During the upcoming parliamentary meeting this year, policymakers are also expected to release details of a new five-year development plan, the 15th such program in China's modern history.