Russian Energy Minister Sergei Shmatko said earlier in the day that Russia had been effectively excluded from talks at an international investment conference in Brussels on the modernization of the Ukrainian gas pipeline network, adding that the conference, convened by the European Commission, was limited to discussions between Ukraine and the EU.
"If Russia's interests are ignored, we will also have to start reviewing the fundamentals of our relations," Putin said. "We would very much like for things not to reach this point."
However Ukrainian news agency Unian said Kiev and Brussels intended to involve Moscow in the modernization of the network if Russia wanted to take part in the project.
"Ukraine, just like the European Union, has the definite intention to attract Russia as a partner in this large reconstruction and modernization program," Prime Minister Yulia Tymoshenko said.
The Russian premier also told journalists that a declaration on the gas market adopted in Brussels by Ukraine and the EU was poorly thought-out and unprofessional.
Putin said the European Commission had refused to combine efforts with Russia to jointly allocate funds to Ukraine, whose economy has been badly hit by the global financial crisis.
"We discussed at meetings uniting the efforts of Russia and the European Commission, but we were told that the European Commission has no money for Ukraine," he said.