Kiev does not see any reasons to pay for Russian gas at the new prices so they are stopping all payments for the duration of negotiations.
So, what's new? They didn't pay before, and they are still not paying...
OK... here is a compromise. Ukraine should clear its debts to Gazprom within the next 7 days. If it is not doing so, then Russia should seize Eastern and Southern Ukraine, and write-off the Ukrainian debts.
I take this as a joke... if not I will cry
Well, every joke has a grain of truth in it, doesn't it?
If you don't pay for your mortgage, the bank takes your house...
That said, the only acceptable way for Russia to annex South-Eastern regions would be after a referendum in those regions. I also think that for such an important question, the number of votes for joining Russia must be over 70-80% (and not the customary 50% as during "normal" voting).
The other option would be buying that land (Alaska precedent). Given that Ukraine has a large debt, the value of that debt should be subtracted from the purchase price. I remember that recently Germany actually offered to buy some islands from Greece and write off their debt, so it seems to be an EU-approved venue.
