Investors had retreated Wednesday as President Donald Trump threatened to launch missiles in response to an alleged chemical attack on civilians in Syria.

This followed days of turmoil on fears of a trade war and a possible privacy regulation clampdown for the tech sector ahead of this week's congressional testimony by Facebook CEO Mark Zuckerberg.

About 10 mins into the day's treading the benchmark Dow Jones Industrial Average was up 0.9 percent at 24,406.23.

The broader S&P 500 and tech-heavy Nasdaq each gained 0.6 percent to reach 2,657.48 and 7,111.21, respectively.

"Never said when an attack on Syria would take place," Trump tweeted early Thursday. "Could be very soon or not so soon at all!"

Trump's tweet appeared to have made the difference for investor sentiment as futures markets turned positive several hours before the open.

"The question is, can the good earnings news overshadow inflammatory headlines on the geopolitical front (should they occur) or will the inflammatory geopolitical headlines serve as a buzz kill on the earnings-reporting party?" said Patrick O'Hare of Briefing.com.

Behemoth money manager BlackRock jumped 2.2 percent after posting quarterly profits that were up nearly 30 percent year on year, handily beating analyst expectations.

Delta Air Lines rose 2.3 percent after posting falling revenues but better-than-expected earnings per share.

Drug store chain Rite Aid gained 3.7 percent after topping earnings estimates, with net income of $767 million compared a year-earlier loss of $21 million,

Facebook was still trading lower, having fallen 1.3 percent amid marathon testimony this week from Chief Executive Zuckerberg, who apologized for a recent data scandal and pledged to protect users.

There was little economic data for investors to focus on, but it was positive: new claims for jobless benefits fell last week, according to the Labor Department, pointing to the continued health of the jobs market.