Data from Market showed five-year CDS raised 31 basis points versus Friday's close to a one-week high of 524 bps.
Moody's downgraded Russia's sovereign rating to Ba1 from Baa3, citing the impact from the Ukraine crisis as well as the steep fall in oil prices and the rouble. Standard and Poor's earlier this year also downgraded Russia to junk.
Russian dollar bonds also fell across the curve on Monday and the rouble shed more than 3 percent against the dollar.