Dow, S&P 500 and Nasdaq set for opening gains after Friday's 770-point blue-chip fall; Oil extends gain as gold slips. Follow along to the action on Monday aft

The Dow dropped more than 750 points Friday as investors fret over the risk of a widening war in the Middle East.

Oil prices leapt, and stocks fell on worries that escalating violence following Israel's attack on Iranian nuclear and military targets could damage the flow of crude around the world, along with the global economy.

The blue-chip Dow Jones Industrial Average was headed for its worst daily drop in almost a month on Friday as the Israel-Iran conflict rattles investors, after easing back from session lows. The Dow was down about 774 points,

Stock futures fell sharply early Thursday, pointing to a rocky open as Wall Street grapples with a tragic plane crash involving Dow component Boeing (BA) and digests a blockbuster earnings report from software giant Oracle (ORCL).

Markets rebounded after Trump said his administration intends to send letters to US trade partners to formally establish new tariff terms.

The Dow Jones Industrial Average (DJINDICES: ^DJI) index edged 3.9% higher in May, with 70% of its 30 constituent stocks ending the month in positive territory. However, the two worst-performing Dow stocks in May -- both from the healthcare sector -- kept the index's rally in check, with one of them plunging over 25%.

The S&P 500 and the Nasdaq composite index lost more than 1 percent. The Dow Jones Industrial Average fell 1.8 percent, dragged down by three of its 30 stocks.