Oil prices fell on Monday, reversing earlier gains after the CEO of Russian sovereign wealth fund RDIF told CNBC that Moscow and Riyadh were “very close” to an oil deal, and as Russia reportedly said it was ready to reduce output, according to Reuters.

U.S. West Texas Intermediate futures fell 5.5% to trade at $26.77 per barrel, while international benchmark Brent crude futures dipped 3.7% to trade at $32.82, according to CNBC.

“I think the whole market understands that this deal is important and it will bring lots of stability, so much important stability to the market, and we are very close,” Kirill Dmitriev of the Russian Direct Investment Fund told CNBC’s “Capital Connection” on Monday. Brent prices edged into positive territory shortly after Dmitriev’s optimistic comments, but have since pared those gains.

Earlier, U.S. crude futures fell more than 10% after a meeting between OPEC and its allies, initially scheduled for Monday, was delayed. The postponement stoked fears on Wall Street that a production cut might face hurdles.

Oil surged last week — WTI and Brent are both coming off their best week on record — as Saudi Arabia called a meeting between OPEC and its allies, known as OPEC+, signaling there could be progress on a production cut.