Taoiseach Leo Varadkar said he was "very satisfied" with the summit conclusions on Brexit which made clear the Withdrawal Agreement was not "up for renegotiation".
EU leaders decided not to move on the British Prime Minister's calls for a legal guarantee that the backstop will not be permanent.
It leaves Theresa May with little more to use to sell the withdrawal agreement to her MPs.
In Brussels this morning Leo Varadkar said he was happy with the backing the EU has given Ireland, and said the Brexit backstop is not just an Irish issue but a European issue.
"As Europe we reaffirmed our commitment for the need for a backstop. An open border between Northern Ireland and Ireland can't be a backdoor to the single market," he said.
"That's why European countries also very strongly support backstop. It is not just an Irish issue, it is very much a European issue as well.
"It is very much a case of in the European Union being one-for-all and all-for-one."
DUP leader Arlene Foster said the reaction of the EU to Mrs May's appeals for help was "unsurprising".
She said: "They are doing what they always do. The key question is whether the Prime Minister will stand up to them or whether she will roll over as has happened previously.
This is a difficulty of the Prime Minister's own making.
"A deal was signed off which the Prime Minister should have known would not gain the support of Parliament.
"If the Prime Minister had listened to our warnings and stood by her public commitments, we would not be in this situation."
PA
