The EU, America and the UK are expected to announce a significant package of sanctions on Russia today.
It's after Moscow formally recognised two separatist regions in Ukraine as independent.
The Taoiseach's among the world leaders who've expressed solidarity with Ukraine, and criticised the Kremlin for breaching international law.
Vladimir Putin used a televised address to make the announcement.
"I consider it necessary to take a long overdue decision to immediately recognise the independence and sovereignty of Donetsk People's Republic and Luhansk People's Republic."
Former deputy supreme commander of NATO, Richard Shirreff, thinks the West's fears about an invasion are legitimate.
"We need to be extremely worried this has been ramping up for some time, and today's announcements are in a sense setting the scene for what may well follow, which will be a Russian invasion of Ukraine."
