Russia announces that it will raise the price Ukraine pays for Russian natural gas by 80%.
The Russian Federal Security Service claims to have killed Rustam Asildarov, the leader of the Islamic State of Iraq and the Levant's Caucasus Province and four other militants in the Dagestan region.
Russia's Federal Security Service (FSB) says it has thwarted two armed Ukrainian incursions into Crimea with at least two killed, including one FSB officer, following a "massive fire fight" with "sabotage-terrorist" groups. Ukraine denies the Russian claims.
Russia's Gazprom halts gas supplies to Ukraine until the Ukrainian government pays in advance for future supplies to replenish the current supplies of gas that it has used up; Ukraine says it has stopped buying from Gazprom because it can get cheaper gas from Europe. Roughly 15% of the gas used in Europe travels through Ukraine, and a previous cut-off of gas supplies in 2009 caused serious disruptions in shipments to EU countries at the height of winter.
Palestinian leaders express disappointment at the refusal of the Middle East Quartet — United States, United Nations, European Union and Russia — to hear their call for unilateral statehood and failure to take a strong stance on Israel's settlement construction at its February 5 meeting in Munich.