Russian President Vladimir Putin and European Commission chief Jose Manuel Barroso met Friday for informal talks on energy security ahead of upcoming European Union and G8 summits. The EU is an important partner for Russia both in political and economic terms, Putin said following the talks at his residence in Novo-Ogaryovo, outside the Russian capital. Secure energy supply is likely to be a key theme of the EU summit on March 23 and 24 in Brussels, as well as of the G8 summit scheduled for St. Petersburg in July. Opions differ within the EU bloc as well as between the members of the G8 as to the form of future energy supply structures. The European Commission additionally this week launched its "Green Book for a European Energy Policy" document, which has as its main objectives sustainable development, competition and security of supply. Russia, the world's largest source of natural fuel, is a major supplier of natural gas to EU nations. European concerns over a disruption to supply have been heightened since the dispute earlier in the year involving Russia's gas giant Gazprom. Barroso, like G8 energy ministers meeting in Moscow had done the day before, urged Putin to ratify the Energy Charter Treaty (ECT), which would break Gazprom's grip on exports as well as prohibit it from cutting supplies as it did to Ukraine and Moldova during January's gas pricing dispute. --More 21 39 Local Time 18 39 GMT