Presidents of Russia, Belarus and Kazakhstan, the three countries making up the Eurasian Customs Union, are set to meet with Ukrainian President Petro Poroshenko in Minsk on Tuesday, media reports said.
Vladimir Putin, Alexander Lukashenko and Nursultan Nazarbayev plan to discuss enhancement of relations in various fields during a meeting on Tuesday, Itar Tass reported.
European Commission officials are also expected to attend the meeting.
Putin is expected to have a range of separate talks in Minsk.
Putin's press secretary Dmitry Peskov did not rule out that Putin might also have a separate meeting with Poroshenko.
“There are many topics for discussion,” he said.
"Their scope includes Ukraine’s internal crisis, the horrendous humanitarian disaster in the east of the country, and the importance of a ceasefire," he added.