Russian President Vladimir Putin said Wednesday that the situation in Ukraine may have negative impact on the markets of the Moscow-led Customs Union (CU).

"Ukraine is a key partner of the CU and a member of the free trade area of the Commonwealth of Independent States (CIS). Extraordinary situation in Ukraine causes serious concerns," Putin told a meeting of the Eurasian Supreme Economic Council.

Putin warned that "extremely difficult crisis" experienced by the Ukrainian economy required the CIS countries to undertake measures to protect their producers and exporters.

Besides, he said, new modes of further cooperation with Ukraine must be worked out.

"We need to do our best to help our partners to depart from the complicated situation they have been in currently," Putin said.

The Eurasian Supreme Economic Council comprises heads of states and governments of Russia, Belarus, Kazakhstan, which are the founding members of the CU and Common Economic Space. In May, they plan to sign a treaty on the creation of the Eurasian Economic Union. Armenia is looking forward to joining the alliance in 2015.

The political crisis has cost Ukraine economically, as the country is facing a possible debt default. Ukraine needs some 35 billion dollars in aid to improve its economy, according to the country's Finance Ministry.