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* Banks stocks gain with Fed expected to hike rates
* Facebook drops as Instagram co-founders resign
* Chevron, Exxon gain as oil prices hit 4-year high
* Intel falls on Raymond James rating cut
* Futures up: Dow 0.34 pct, S&P 0.29 pct, Nasdaq 0.22 pct
By Amy Caren Daniel
Sept 25 (Reuters) - U.S. stock index futures edged higher on Tuesday, as energy companies gained with oil prices at four-year highs, although the U.S.-China trade tension and the upcoming Federal Reserve meeting prompted caution.
The U.S. central bank is widely expected to raise benchmark interest rates on Wednesday, a move that would make cash the most attractive it has been in about a decade and lower the appeal of stocks.
The Fed's guidance on the path for future rate hikes will also help steer investments, especially as the trade dispute between the United States and China escalates.
A day after Wall Street was buffeted by the latest round of tariffs, a senior Chinese official said trade talks would be difficult while Washington is putting "a knife to China's neck."
"The Federal Reserve may not seem very worried about growing tensions with the global trade dispute. So far there are no clear indications that global trade tensions are weighing on the U.S. economy," Hussein Sayed, chief market strategist at FXTM, wrote in a note.
"The most interesting part ... is how the Fed sees the economy performing in 2019 and beyond. Ongoing support from the fiscal stimulus will gradually begin to fade and higher borrowing costs along with a stronger dollar will likely begin impacting future corporate earnings."
Shares of big U.S. lenders rose in premarket trading, with Bank of America, JPMorgan, Wells Fargo and Citigroup up between 0.5 percent and 0.7 percent.
However, Facebook fell 2.5 percent after co-founders of its photo-sharing app, Instagram, resigned with scant explanation for the move.
At 7:12 a.m. ET, Dow e-minis were up 90 points, or 0.34 percent. S&P 500 e-minis were up 8.5 points, or 0.29 percent and Nasdaq 100 e-minis were up 16.5 points, or 0.22 percent.
Energy stocks were poised to boost markets for the second session in a row as Brent oil prices shot to a four-year high due to upcoming U.S. sanctions on Iranian crude exports and the apparent reluctance of OPEC and Russia to raise output to offset the potential hit to global supply.
Dow-components Chevron and Exxon Mobil rose 0.7 percent and 0.5 percent, respectively.
Intel fell 1 percent after Raymond James downgraded the stock, citing mounting headwinds against the chipmaker.
Microchip, Analog Devices and ON Semiconductor were trading between flat and down 1.3 percent after their shares were downgraded by Raymond James.
On the macro front, the U.S. Conference Board is expected to report that its consumer confidence index slipped to 132.0 in September from a reading of 133.4 in August. The report is due at 10 a.m. ET. (Reporting by Amy Caren Daniel in Bengaluru)