MOSCOW, Oct. 17 - Russian President Dmitry Medvedev and his Ukrainian counterpart Viktor Yanukovych will discuss the euro zone situation and, in the case of the Ukrainian interest, the formation of the Customs Union in Donetsk on October 18, Russian Presidential Aide Sergei Prikhodko told a Monday press briefing.

"If Yanukovych is interested, we may share information concerning the formation of the Customs Union of Belarus, Kazakhstan and Russia," he said.

"The strengthening of this integration union will have an effect on the bilateral relations with Ukraine this way or another," he said.

Medvedev and Yanukovych will attend the 2nd Russian-Ukrainian Interregional Economic Forum in Donetsk on Tuesday.