I would take the equity risk if I could buy Surgutneftegaz on a PE of 1 http://finance.yahoo.com/quote/SGTZY?ltr=1. I did read that the dividend yield was high but yahoo are reporting it at 2.02% . Here is http://www.citibank.com/ipb/europe/wealthproducts/bonds.htm I guess Gazprom have USD bonds.
Is IB save? Generally the questions is answered above BUT what about some crazy sanctions against Russians in the future. You never know. So even with brokers you might consider diversification, maybe an Asian or European broker, but I can't give any advice on that but consider your risk.
If I was Russian I would be all over the Surgutneftegaz preferreds yielding double digits. Convert the dividends into dollars and then ship them out the country as diversification. I don't think I would reinvest them. Googling the ownership of Surgutneftegaz is an interesting read if you are into russian politics!