Ukraine’s President Viktor Yushchenko chaired a cabinet meeting in Kiev where there was an examination of the possibility of using a 1994 nuclear disarmament pact to appeal to the US and Britain for help in the dispute.
Mr Yushchenko and his top ministers discussed "possible consultations with the states that in 1994 signed the memorandum on security guarantees" given to Ukraine in exchange for its renunciation of nuclear weapons, the president's office said in a statement.
Kiev's renewed reference to the 1994 nuclear disarmament agreement marked a significant raising of the political stakes surrounding the dispute.
With time running out ahead of a January 1 deadline set by Russia, Ukrainian Energy Minister Ivan Plachkov was dispatched to Moscow for another round of talks with Russian officials to try to break the impasse.
The meeting concluded without result but will continue on Thursday, news agencies quoted Mr Plachkov as saying.
He said there had been "movement in the negotiations" and that "compromises are possible." However, Russian officials made no comment.
Russia angrily rejected Ukraine's citing of the 1994 agreement as "having no basis."
The agreement rules out threats of use of force or attacks on Ukraine's territorial integrity, political independence, along with economic coercion aimed at subverting Ukrainian sovereignty, the Russian foreign ministry said in a statement.
"The shift to European prices for delivery and transit of gas can in no way be regarded as a threat to the realisation of Ukraine's sovereignty rights," it added.
This was clear "since Ukraine itself has spoken in favour of a shift to market" prices, the statement continued.
There was no immediate comment from Washington or London on the possibility that Ukraine might ask for help.
Russia's state-run gas giant Gazprom has cast the argument as strictly commercial despite claims by Kiev that it is politically-motivated.