Talks with Russia crumbled on Friday, forcing Ukraine to begin preparing for a natural gas shutoff.
The long-running dispute over the cost of natural gas came to a halt Friday, and is threatening the European Union's supply of gas as well, Reuters reports.
Ukraine depends on Russia for 60 percent of its natural gas, and 80 percent of Russian natural gas exports to Europe are transported through Ukraine, according to the Energy Department's stat shop.
"Ukraine is getting ready for the worst scenario, a cut in Russian gas supplies," Andriy Kobolev, chief executive of Ukrainian gas company Naftogaz, was quoted as saying by a company spokeswoman, according to Reuters.
Turning off the natural gas flow will heighten an already tense political crisis between Russia and Ukraine. It will also add fuel to the calls for expediting natural gas exports to non-Free Trade Agreement countries among U.S. lawmakers.
Ukrainian Prime Minister Arseniy Yatsenyuk issued a notice to the energy sector, ministries and regional authorities to prepare of a stop in supply Friday.