Taoiseach Enda Kenny has described the American airstrike on Syria as a "matter of grave concern", writes Elaine Loughlin.
Dozens of US cruise missiles were fired at an airbase in Syria from where it is believed a suspected chemical weapons attack was launched earlier this week.
The attack, ordered by President Trump, has has raised tensions between Russian and the US.
Speaking in Berlin this afternoon, Mr Kenny said the chemical weapons attack which the Assad regime has been accused of is a "war crime".
"This is a matter of grave concern internationally in terms of politics," he said.
"And obviously American government made its decision as a reaction to the illegal use of chemical weapons. In my view the use of chemical weapons is a war crime.
He added that the use of such chemicals is "an act of aggression that is beyond anything to do with what you might call conventional warfare".
"Clearly warnings were given by the American government to those in the vicinity of the particular base that was bombed last evening," Mr Kenny said.