Oil futures were slightly lower early Friday, but on track for a fourth straight week of gains after wider sanctions against Russia’s energy industry tightened supply.

Oil prices climbed on Friday, heading for a fourth weekly gain, driven by concerns over tighter supply following U.S. sanctions on Russian oil producers and signals from a Federal Reserve official of potential interest rate cuts.

Oil price risks are skewed to the upside due to sanctions supply disruptions, said Samantha Dart, co-head of global commodities research at Goldman Sachs. The Energy Select Sector SPDR Fund ETF (XLE) is up 8.

US drivers could see lower gas prices this year and next as oil supply outpaces demand. The US will continue to ramp up output from record levels, the EIA said.