Speaking in the Russian Black Sea resort of Sochi on Monday, Mr Putin said the deal was "at the very least ill-considered and unprofessional because discussing such issues without the main supplier is simply not serious". Despite their bitter rivalry, Ukrainian President Viktor Yushchenko and Prime Minister Yulia Tymoshenko were both in Brussels for an international conference with the European Commission, the World Bank and other key lenders. The EU gets 80% of its gas supplies from Russia via a network of more than 13,000km (8,060 miles) of Ukrainian pipelines, some of which are 40 years old.
Tymoshenko is the Russian prime minister.