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By Shashwat Chauhan and Kanchana Chakravarty

May 30 (Reuters) - Wall Street's main indexes were set for a lower open on Friday as trade worries deepened after U.S. President Donald Trump accused China of violating a tariff agreement, while investors assessed the latest inflation data.

"China, perhaps not surprisingly to some, HAS TOTALLY VIOLATED ITS AGREEMENT WITH US. So much for being Mr. NICE GUY!," Trump said in a post on his Truth Social platform.

"We went from a place where it felt as though investors had a pretty good handle on the direction of trade and tariffs and now that picture has become very confusing," said Art Hogan, chief market strategist at B Riley Wealth.

Futures tied to the main indexes cut some losses after data showed U.S. consumer spending increased marginally in April, with the year-on-year reading increasing to 2.1% after advancing 2.3% in March. The Fed tracks the PCE price measures for its 2% inflation target.

Traders continued to bet that the U.S. central bank will cut its target for short-term borrowing costs in September

At 08:48 a.m. ET, Dow E-minis YMcv1 were down 110 points, or 0.26%, S&P 500 E-minis EScv1 were down 19.25 points, or 0.33% and Nasdaq 100 E-minis NQcv1 were down 52.25 points, or 0.24%.

Most megacap and growth stocks inched lower in premarket trading, with Nvidia NVDA.O off 0.5% after gaining in the last session on reporting robust quarterly revenue growth. Tesla TSLA.O lagged with a 1% fall.

Despite the losses, the S&P 500 .SPX and the Nasdaq .IXIC are on pace for their best monthly showing since November 2023, while the Dow .DJI is also set for a near 4% monthly advance.

It has been a volatile month for stocks as Trump's on-and-off trade moves kept investors on edge, though his softening stance on tariffs has helped the S&P 500 rebound from its April lows. The benchmark is now about 4% lower than its all-time high hit in February.

U.S. equities had initially rallied in the previous session, after the Court of International Trade ruled late on Wednesday to effectively block most levies imposed since January, without addressing some industry-specific tariffs.

However, a federal appeals court on Thursday temporarily reinstated most of the tariffs and ordered the plaintiffs in the cases to respond by June 5 and the administration by June 9.

Hopes of more deals between the U.S. and major trading partners, along with upbeat earnings and tame inflation data, are behind most of the gains in equities this month.

Among other moving stocks, chipmaker Marvell Technology MRVL.O shed 3.9% despite forecasting second-quarter revenue above estimates.

Ulta Beauty ULTA.O gained 10% after the cosmetics retailer raised its annual profit forecast after beating quarterly results.

Shares of drugmaker Regeneron REGN.O dropped 12.1% after its experimental drug for patients with a type of lung condition commonly called "smoker's lung" failed a late-stage trial, although it succeeded in another.

(Reporting by Shashwat Chauhan and Kanchana Chakravarty in Bengaluru; Editing by Maju Samuel and Devika Syamnath)

((Shashwat.Chauhan@thomsonreuters.com; Kanchana.Chakravarty@thomsonreuters.com))