The Foreign Affairs Minster says international sanctions against Russia will be clear and firm.
It follows the Kremlin's formal recognition of two separatist regions in Ukraine as independent.
Vladimir Putin announced last night that he was sending troops to the two breakaway regions, describing them as 'peacekeepers'
The EU, UK and US are working together to adopt a range of sanctions.
Minister Simon Coveney says that while diplomacy needs to continue, Russia is clearly in breech of international law and the west must act to help Ukraine.
"You don't send peacekeepers in tanks and attack helicopters.
"This is essentially setting the scene as a stepping stone for a military takeover of parts of Ukraine.
"I think we need to call it out for what it is. and the EU needs to respond to that."
