Sikorski: Putin must follow international law on Crimea
11 March 2014 Last updated at 13:35 GMT
Polish Foreign Minister Radoslaw Sikorski talks about the fear of Russia invading Ukraine and draws a parallel with events leading up to World War Two when Nazi Germany invaded other countries.
He told HARDtalk's Shaun Ley that only Russia's President Putin could ensure a peaceful end to the crisis.
You can see the full interview on BBC World News at 16:30 and 21:30 GMT on Tuesday 11 March and on the BBC News Channel on Wednesday 12 March at 00:30 GMT.