OPEC and its allies could boost oil production by more than the 1 million barrels a day agreed last month if needed, Russia’s Energy Minister Alexander Novak said.

“I can’t rule out that if there is a need for more than 1 million barrels we will be able to quickly discuss it all together and make all necessary decisions,” Novak told reporters in Moscow. OPEC+ has “all needed tools,” if necessary, he said.

Oil prices have remained near their highest in more than three years despite pledges by Russia, Saudi Arabia and their allies last month to boost production. Supplies are being strained by deepening losses in Venezuela, erratic flows from Libya and the prospect of renewed U.S. sanctions on Iran.

Novak didn’t comment on whether he discussed the option of raising supply by more than agreed amount with his Saudi Arabian counterpart Khalid Al-Falih during their phone conversation earlier this month.

The question of how much supply will be increased by remains a contentious topic in the coalition of producers often referred to as OPEC+.

Iran, facing the loss of customers scared off by U.S. penalties, disputes that the Organization of Petroleum Exporting Countries agreed to any significant output increases at its meeting in late June. Output limits assigned in late 2016 still apply, and any country that exceeds these is betraying the organization, it has said.

--With assistance from Grant Smith