The price of Russia's ruble-denominated government debt fell Monday, sending borrowing costs higher. Stock trading has remained closed, with no word on when it might reopen.

The central bank bought bonds to support prices. It has imposed wide-ranging restrictions on financial transactions to try to stabilize markets and combat the severe fallout from Western sanctions that have sent the ruble sharply lower against the US dollar and the euro.

Rating agencies have downgraded Russia's bonds to ``junk'' status. Russia's finance ministry last week flirted with default by threatening to pay foreign holders of dollar bonds in massively devalued rubles before sending the money in dollars.

Stocks last traded on Feb. 25, the day after the invasion started, and sent the main stock index sharply lower.