OREANDA-NEWS  The global price of oil could jump by about 40% to $140 per barrel if a proposed price cap on Russian crude is not imposed, a senior US Treasury official told Reuters on Tuesday.

The warning comes as Treasury Secretary Janet Yellen started a trip to Asia on Tuesday to win support for the price-cap proposal. She plans to hold talks on the issue with Japanese Finance Minister Shunichi Suzuki. She is also expected to broach the subject during meetings with G20 finance ministers in Indonesia and during a stop in South Korea.

An unnamed Treasury Department official also told Reuters that Washington has proposed an exception to the ban on maritime insurance for imports of Russian crude that is priced below the cap to prevent millions of barrels from being stranded.

Last month, G7 leaders discussed imposing a price cap on Russian crude of about $40 to $60 per barrel, in order to limit Moscow’s revenue from energy sales. The idea was first introduced by Yellen earlier this year and was then taken up by the G7, which is considering the possibility of an embargo on the transport of Russian seaborne crude oil unless it is purchased at or below a price to be agreed with international partners.

Oil prices gained slightly on Wednesday, with the price of benchmark Brent trading above $100 a barrel and US West Texas Intermediate at $96.60 per barrel.