Russia's energy minister and EU Energy Commissioner Guenther Oettinger have reached a tentative agreement for three-way talks between Russia, Ukraine and the EU on Ukraine's debt to Moscow for gas to be held later this week, the Russian ministry said..

"The meeting is planned for May 2 in Warsaw," the Russian Energy Ministry said, adding that it expected the Ukrainian delegation to confirm its participation soon. Russia had earlier proposed the talks be held on Monday in Moscow.

President Vladimir Putin has warned that Russia could halt supplies to Ukraine over non-payment of more than $2 billion in debt for gas, potentially reducing deliveries to European customers who receive gas via pipelines in Ukraine.