BRUSSELS, November 5. /TASS/. The European Commission (EC) is closely watching the implementation of a gas deal reached between Russia and Ukraine, including Ukraine’s gas debt repayment and the resumption of natural gas supplies, an EU source said on Wednesday.

"We proceed from the fact that all the sides will fulfill their obligations thoroughly and conscientiously," the source said.

European Commission Vice-President for Energy Union Maros Sefcovic will now take the place of former EU Energy Commissioner Guenther Oettinger in gas talks between Russia and Ukraine, the EC press office said on Wednesday.

Russia and Ukraine agreed at their consultations with the EU’s mediation in Brussels on October 31 on the resumption of Russian natural gas supplies for Ukrainian consumers, their guaranteed transit to Europe across Ukraine and Kiev’s partial gas debt repayment.

Ukraine has to repay $3.1 billion for the supplied Russian natural gas until the end of this year.

Gazprom confirmed on Wednesday it had received the first tranche of $1.45 billion as Kiev’s debt repayment. Ukraine has to pay the remaining $1.65 billion to Gazprom until December 31, 2014. The repayment of the first and second debt tranches are “a prerequisite for Russian natural gas supplies after December 31, 2014."