The US decided on Monday to stop Moscow from accessing about $600 million in reserves held in US banks, even if it is to pay interest on sovereign debt.

The move is yet another way to increase financial pressure on the Kremlin by further restricting access to the US dollar through reserves held in the United States.

So far, the sanctions imposed by Washington against Russia, while freezing the Kremlin's access to reserves held in US banks, still allowed Moscow to use these funds to pay coupons on dollar-denominated bonds.

Now the Treasury Department has decided to end this exception, which calls into question Moscow's compliance with sovereign debt coupons, including $552.4 million, according to Reuters data.