Kerry and Lavrov in Last-ditch Ukraine Talks

US Secretary of State John Kerry has been meeting Russian Foreign Minister Sergey Lavrov in London. It is their last opportunity to talk, before a referendum is held in Ukraine's Crimea region - on whether it should become part of Russia. The US wants assurances that Russia would not annex Crimea. But Russia said it has the right to protect its compatriots in the whole of Ukraine.