RTE reporter Tony Connelly has been moved to a basement in Kyiv amid fears of more Russian air strikes.
The RTE Europe Editor is in the Ukrainian capital covering the invasion along with dozens of other journalists on site.
Mr Connelly tweeted this morning: "Just been moved down to the basement of the hotel in Kyiv, amid fears of more Russian airstrikes."
He added: "Airborne Russian assault now underway in Kyiv, according to eye witness and video footage."
Dozens of explosions have been reported across the Ukraine as Russian forces attack as part of an operation launched by President Putin overnight.
Within moments of confirming a military operation in the neighbouring nation, explosions rung out and could be heard across a number of eastern cities.
More than 40 people are said to have been killed so far.
Ukraine President Volodymyr Zelenskyy quickly announced martial law across all territories.
An emergency meeting of EU Leaders is set to take place on Thursday evening, where it is believed strong sanctions will be enforced on Russia.
Speaking outside Government buildings, Micheál Martin said: "Today's invasion and attack is an outrageous and moral breach of the most fundamental and basic principles of international law. Our thoughts must be with the innocent people on Ukraine. We stand with them.
"The UN Charter requires all countries to refrain from the threat or use of force against political independence and territory of any state. Today's use of brute force is a serious affront."
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