(Reuters) -U.S. stock index futures reversed early gains on Thursday, as worries about the fallout of U.S. tariff policies crept back into markets a day after the Federal Reserve stuck to its monetary easing plans for the year but warned of an uncertain economic backdrop.

Global markets have been roiled with volatility over the past few weeks as investors were concerned that President Donald Trump's aggressive stance on trade policies could stoke inflation, tip the economy into a recession and disrupt the Fed's monetary policy easing cycle.

The Fed maintained current interest rates on Wednesday as expected and reaffirmed its forecast for two 25 basis point reductions by the year-end.

However, adding to markets' unease, the central bank also projected slightly reduced growth and increased inflation for the year, alongside a modest uptick in the unemployment rate by 2025.

"The Fed remains very concerned about the impact of tariffs on inflation," said Achilleas Georgolopoulos, senior market analyst at brokerage XM.

"Stagflation comes to mind - a combination of weak growth and strong inflation - something the U.S. has not experienced for a protracted period of time since the early 1980s."

Market participants are currently factoring in 63 basis points of easing from the Fed this year, placing odds of 25 bps rate cut in June at 60%, according to CME Group's Fedwatch tool.

All the three major stock indexes close higher by over 1% each in the previous session. However, the S&P 500 remains down 3.5% so far this year and the Nasdaq is lower by 8%. The indexes' declines have erased all gains since President Donald Trump's November election.

At 07:15 a.m. ET, Dow E-minis were down 145 points, or 0.35%, S&P 500 E-minis were down 26 points, or 0.45% and Nasdaq 100 E-minis were down 117.75 points, or 0.60%.

The CBOE volatility index, also known as Wall Street's fear gauge, gained 0.66 points and was last at 20.56.

Gold prices hit a new record high, another sign of lingering investor worries.

A key focus for the markets will be the upcoming implementation of new reciprocal and sectoral tariffs, slated to take effect on April 2.

On the data front, markets will also assess a weekly report on jobless claims and the Philadelphia Fed's business index for March.

Accenture ( ACN ) rose 1.25% in premarket trading after the IT services provider raised its full-year revenue forecast on artificial intelligence services demand.

Growth stocks reversed gains. Nvidia slipped 0.6%, while Meta, Amazon.com and Microsoft were down marginally.

U.S.-listed shares of PDD Holdings ( PDD ) dropped 6.3% after the Temu parent missed estimates for fourth-quarter revenue.