"According to our knowledge Ukraine has asked for an increase of transit payments by Russia for [crude oil] shipments as of next year," Fico told a news conference.
"Therefore Russia has warned the EU and us about possible disruptions of crude oil shipments from as early as Jan. 1," Fico added.
The possible crude oil supply disruption is "due to [a] payments dispute between these two countries," Fico said, the same as last winter when Russia shut down natural gas shipments to the European Union via Ukraine.
"But unlike the gas crisis of last January, any possible oil shipment disruptions can be covered by [crude oil] supplies via alternative routes," Fico said.
Russian crude oil supplies account for over 90% of Slovakia's domestic demand. The eastern EU country can get alternative oil supplies other than Russian shipments via rail, Slovak industry minister Lubomir Jahnatek said.
Slovakia has crude oil and fuel reserves to cover more than 94 days of its domestic demand.
"These reserves are split about 50%-50% between crude oil and oil products," Fico said.
The Czech Republic has also prepared itself for the risk of an oil supply cut from Russia by maintaining reserves that can cover the local demand for more than 90 days, Czech Industry Ministry spokesman Tomas Bartovsky said.
"We went through similar situations before in 2008 and 2007 and therefore we're prepared," Bartovsky said.
Czechs are less vulnerable than their Slovak neighbors, since Czech oil refineries can be switched fully to crude oil supplies from the country's alternative pipeline, known as IKL. The pipeline connects the Czech Republic with the Adriatic sea port of Trieste in northern Italy and delivers crude oil from the Persian Gulf region. The IKL pipeline covers 30% of local demand.
"IKL is capable of covering the entire local demand if necessary but it would require securing shipment slot contracts in the pipeline system," Bartovsky said, adding that ramping up the IKL oil shipments would take some time.
Hungary's crude reserves are sufficient to supply the country for 90 days of average consumption, MOL said in a release.
"MOL is prepared to handle the situation; following a possible halt of supplies via the Druzhba pipeline, the reverse of flows on the Adriatic pipeline would become our prime task, which would take some 25-30 days," MOL said.
"Even if the row escalated between Russia and the Ukraine, Hungary's crude supply wouldn't be at threat," MOL added.
For several months from late spring through late summer of 2008, Russia disrupted its oil shipments to the Czech Republic and Slovakia over a dispute concerning transit fees between Moscow and Kiev.
"However, unlike last year's natural gas shipment crises, any possible crude oil shipment disruptions are more easily manageable and there is no need for concerns over insufficient fuel supplies on [the Czech] market," Bartovsky said.