Russia's former president Dmitry Medvedev said Tuesday that a reported proposal from Japan to cap the price of Russian oil at around half its current price would lead to significantly less oil on the market and could push prices above $300-$400 a barrel.

Commenting on the proposal, which was reportedly put forward by Prime Minister Fumio Kishida, Medvedev said that Japan "would have neither oil nor gas from Russia, as well as no participation in the Sakhalin-2 LNG project" as a result.

G7 leaders agreed last week to explore feasibility of introducing temporary import price caps on Russian fossil fuels, including oil, in an attempt to limit Russian resources to finance its military campaign in Ukraine.

JPMorgan Chase & Co. analysts have also warned that global oil prices could reach a “stratospheric” $380 a barrel if Russia retaliates to U.S. and Western sanctions with cuts in crude oil,

The Group of Seven’s latest ammunition against Russia for its unprovoked war in Ukraine has been to cap the price of Russian oil.

Russia is in a relatively robust financial position that would permit it to cut daily crude oil production by  5 million barrels a day, Bloomberg reports JPMorgan analysts as writing in a client note.

“The most obvious and likely risk with a price cap is that Russia might choose not to participate and, instead, retaliate by reducing exports,” the analysts wrote. “It is likely that the government could retaliate by cutting output as a way to inflict pain on the West. The tightness of the global oil market is on Russia’s side.”

• JPM: Oil Could Reach $380 If Russia Retaliates
• Russia Seizes Sakhalin Gas Project, Raises Stakes With West