Donald Trump spoke on the phone Saturday with King Salman bin Abdulaziz of Saudi Arabia, days after the U.S. president’s latest criticism of OPEC over high oil prices.

The pair discussed the stability of the oil market and the strategic partnership between the two countries, Al Arabiya TV reported, without providing more details. The White House said Trump and the King spoke on “issues of regional concern.”

Hedge funds are watching Trump’s back-and-forth with the kingdom for any signs that the U.S. might take action against the country or other members who belong to the cartel.

Trump’s been increasing the pressure on OPEC, saying it’s pushing oil prices too high. At its latest meeting, the group ignored his call to reduce oil prices.

This week, Trump again said he wasn’t happy with OPEC, Middle East nations and oil prices, asserting that the producer group was causing prices to rise while benefiting from protection of the U.S. military. Trump has gone after OPEC multiple times this year, including while speaking at the United Nations on Sept. 25.

“OPEC and OPEC nations, are, as usual, ripping off the rest of the world, and I don’t like it,” Trump said in an address to the United Nations General Assembly in New York. “We want them to stop raising prices. We want them to start lowering prices and they must contribute substantially to military protection from now on.”

Brent crude, the international oil benchmark, surged on Friday to a fresh 4-year high above $83 a barrel as the market braces for the impact of the U.S. energy sanctions on Iran.

Gasoline pump prices are on the rise in the U.S., squeezing consumers weeks before critical mid-term elections. The national unleaded average gas price was $2.875 per gallon on Friday, according to AAA, up 1.4 percent in the past month and 11.7 percent higher than a year ago.