Russia deploys a second anti-air S-400 missile batallion in Crimea.
Two battalions with S-400 systems would take up combat duty in Crimea in the beginning of 2018
- Radio Free Europe
- The Security Service of Ukraine bans Yuliya Samoylova, Russia's entrant in this year's Eurovision Song Contest, from entering the country. This follows allegations that she had toured in Crimea following its annexation by Russia.
- President of Turkey Recep Tayyip Erdogan affirms Turkey has paid a deposit on the purchase of Russian S-400 missile systems.
- Ukraine sues Russia at the International Court of Justice, accusing the latter of being engaged in acts of "terrorism" and "discrimination" in eastern Ukraine and Crimea.
- Ukraine starts a missile test near Crimea, annexed by Russia in 2014, while Russia puts its air-defense and naval forces in the region on high alert.
- Russia deploys its S-400 missile system in Kaliningrad, an exclave between Poland and Lithuania, in response to "NATO expansion" near its borders. The United States criticizes the move as "destabilizing" to Europe. Russia announced the planned deployment over a decade ago.