Israel launched a wave of strikes across Iran on Friday that targeted its nuclear program and military sites, killing at least two top military officers and raising the prospect of an all-out war between the two bitter Middle East adversaries. It appeared to be the most significant attack Iran has faced since its 1980s war with Iraq.

European stocks are poised to open sharply lower, meanwhile, with U.S. stock futures also falling. Investors fled to safe-haven assets Friday after a series of Israeli airstrikes on Iran marked a major escalation of conflict in the region.

Israeli strikes on Iran on Friday and Tehran's vows of reprisals have brought the two Middle East adversaries closer to an all-out war, which also threatens to draw in the United States, at least to some degree.