The G7 is still working to set a price cap for Russian oil, but adding more nations to the program is not necessary for success, US Treasury Secretary Janet Yellen said on Friday.

Australia recently joined the Group of the Seven Prosperous Democracies and the European Union in backing the move aimed at depriving Moscow of a key source of funding for its war in Ukraine and to cool soaring energy prices.

Yellen said a broader coalition was not needed because the cap would be set by Western financial service providers and insurance companies having to honor a maximum price in contracts for Russian oil supplies.

“We’re not trying to add more countries to a coalition,” Yellen said at a press conference at the IMF’s annual meeting in Washington.

The United States has imposed an embargo on Russian oil, while the European Union will ban most imports from December.

“None of the coalition countries are buying Russian oil or will buy Russian oil,” Yellen said.

“And none of the countries outside the coalition are really important providers of these financial services,” she added.

These countries will have access to Western insurance companies’ services “as long as they buy below the cap,” Yellen said.

“We need to make them understand that that is the condition they have to access these services and that we will make sure western companies comply, but frankly we are not asking anything of other governments.”

Moscow has warned it would cut oil supplies to countries that impose such a cap.

Oil prices rose to almost $140 a barrel in March after the Russian invasion. The international benchmark Brent has been hovering around $90 since then.

Western officials have said the price of Russian crude would remain above production costs, giving Moscow still an incentive to supply importing countries.

Yellen mentioned a figure of $60 this week but clarified on Friday that such a number is under consideration.

“No decisions were made,” she said.