Investors are bracing for how U.S. stock market futures respond after Israel and Iran ramped up their aerial attacks early Sunday, and after President Donald Trump suggested that “it’s possible” the U.

Futures on Wall Street are currently in cautious mode as they await further details on the ongoing hostilities between Israel and Iran, which have now entered the fourth day. Futures of all three indices are currently trading at the flat line,

Brent crude rose as much as 5.5% in early Asian trading after Israel and Iran continued attacks on one another’s territories over the weekend.