With Russia announcing that it made a debt payment in rubles this week, concerns are rising that Moscow will soon default on external loans for the first time in more than a century. This might not be accepted by Russia’s foreign debtholders and could put the country on a path to a historic default. The Russian ministry of finance said in a statement that it tried to make a $649 million payment toward two bonds to an unnamed US bank—previously reported as JPMorgan Chase—but that payment was not accepted because new US sanctions prohibit Russia from using US banks to pay its debts.

Russia said it has instead transferred the funds in rubles into a special bank account with Russia’s National Settlement Depository, the country’s securities regulator. The ministry added that once the country is allowed to access foreign exchange markets—not something that will happen for the foreseeable future due to sanctions—it will decide whether to allow bondholders to convert the ruble payment back into dollars or euros.

Tightened sanctions placed on Russia this week after evidence of alleged war crimes—the killing of civilians in the town of Bucha during Russian military occupation—barred it from using any foreign reserves held in US banks for debt payments. The US has been attempting to force Russia to use its foreign currency reserves (or any revenue from oil and gas sales) in order to deplete the country’s financial resources. The sanctions placed on Russia this week barred the country from using any of its foreign reserves held in US banks for debt payments.

Previously, the treasury department had been allowing Russia to make debt payments, which stopped Russia from defaulting last month when it transferred a payment on March 17. Russia has not defaulted on its foreign debts since the Bolshevik Revolution in 1917, when the collapse of the Russian Empire led to the creation of the Soviet Union. Even in the late 1990s during Russia’s sovereign debt crisis the country was able to continue to pay foreign debts with the help of international aid, although it did default on its domestic debt.