The prime ministers of Russia and Ukraine are to oversee the signing of a gas supply and transit agreement in Moscow later today.
Vladimir Putin and Yulia Tymoshenko reached the deal to restore Russian natural gas supplies to Europe via Ukraine after marathon talks on Sunday.
It means Ukraine will start paying a higher price for Russian gas next near.
The dispute over unpaid bills and price hikes has disrupted gas supplies to much of Europe.
A spokesperson for the Russian government said gas should be moving again by Tuesday.
Meanwhile, in the Bulgarian capital Sofia, protestors gathered to call for the reopening of two Soviet-era nuclear reactors.
The country, the poorest in the EU, faces economic woes as a result of the global downturn and has been hit hard by the Russia/Ukraine gas dispute.
Bulgaria has been told not to restart the reactors as they fail to meet EU safety standards.