Ryanair has suspended all of its flights to and from Ukraine for at least the next fortnight.
The airline also revealed that all flights to and from Ukraine will be removed from sale for at least the next four weeks.
It comes after Russia launched a full-scale invasion in the early hours of Thursday morning.
Ryanair confirmed that all affected passengers will receive email notices this morning, while the airline remains committed to services to and from Ukraine and looks forward to restoring flights as soon as it is safe to do so, Buzz.ie reports.
The move comes a week after Ryanair chief executive Michael O'Leary vowed to continue offering services to and from Ukraine until the point that a Russian invasion took place.
"Is it our duty and obligation to support the people of Ukraine as long as there is no war or missiles flying there," O'Leary said at the time.
He added: "People need to get home and people want to leave and fly abroad to the EU - airlines have to provide that service."
Russian president Vladimir Putin's decision to declare war on Ukraine overnight prompted airlines to avoid Ukrainian airspace.
Putin announced a "special military operation" in the early hours of Thursday morning, sparking concerns that the invasion of Ukraine could lead to the biggest war in Europe since World War II.
A number of major Ukrainian cities have reportedly been attacked already; with explosions heard in Kyiv, Kharkiv, Mariupol and Dnipro.
At the time of writing, the Ukrainian government confirmed that the death toll of its soldiers has risen to five.
Minister for Foreign Affairs Simon Coveney revealed that two Irish families are currently in Ukraine for surrogacy services and his department is working with them to ensure their safe departure from the country.
"We have been planning for this for a while. There are contingency plans in place. And we will obviously act in a way that maintains the safety of our people," Coveney told RTE's Morning Ireland.
