Captain Rory Best has passed on the Ireland squad's sympathies to the victims and families of those affected by the New Zealand attack.
A gunman shot dead 49 people and wounded more than 40 at two Christchurch mosques.
The team are in Cardiff to face Wales in the Six Nations tomorrow afternoon and count New Zealanders Bundee Aki, head coach Joe Schmidt and scrum coach Greg Feek among their number.
Best said: "Waking up this morning to that news, it's really, really tragic. Our heartfelt sympathies go out to all the families and anyone in that greater Christchurch area and anyone with family over there.
"We have Joe, we have Greg Feek, Bundee's family in New Zealand, [former Ireland player and current Crusaders coach] Ronan O'Gara, a good friend of a lot of the squad, he's over there as well.
"So it's just one of those tragedies that's really hard to put into words.
"All we can do is pass on our deepest sympathies. It was the talk of the team room this morning at breakfast because everyone was shocked and saddened by it."