The EU is considering sanctions against Israel if it refuses to comply with rulings from the International Court of Justice, the Tánaiste has said.
Speaking in Brussels on Monday after a meeting of foreign ministers, Mr Martin said the issue had been discussed "for the first time at an EU meeting".
It comes after at least 45 people were killed by an Israeli airstrike on a refugee camp housing displaced civilians on Sunday.
Survivors said families were about to sleep when the strike hit the Tel al Sultan neighbourhood, where thousands were sheltering after Israel began a ground offensive in the east of Rafah.
Smoke rises following Israeli air strikes near the Rafah Crossing in Palestine, 7-5-24. Image: dpa picture alliance / AlamyMore than half of the dead were women, children, and elderly people, health officials in Gaza said, adding that because of the severe burns suffered by some of the injured the number of dead was likely to rise.
Israel has kept up its offensive despite a ruling by the International Court of Justice (ICJ) in The Hague on Friday ordering it to stop.
Micheál Martin branded the attack as "barbaric" and said Israel has to abide by the court ruling.
"There was a strong discussion on the provisional orders of the International Court of Justice and there was a very clear consensus about the need to uphold the international, humanitarian legal institutions such as the International Court of Justice and indeed the ICC," he said.
Mr Martin said there were "very clear views" that Israel should adhere to ICJ orders to cease its Rafah offensive and open the border crossing.
"One of the conclusions was to convene a meeting of the EU-Israeli Association Council to raise our grave concerns and to put it to Israel, and to seek from Israel a response, in terms of complying with the orders of the court," he said.
Sanctions
Asked if this approach included EU sanctions against Israel, Mr Martin told reporters: "For the first time at an EU meeting, in a real way, I've seen significant discussions on sanctions and what if."
He said "some distance" remains between talking about a sanctions-based approach and agreement at an EU Council level.
"There is a lot of concern there now across the EU Council and member states in respect of what is a clear situation in which the International Court of Justice have ruled, have made provisional orders and the EU has always upheld the independence of that court and the need for nations to comply with it," he said.
'Hell on Earth'
UNRWA Commissioner-General Philippe Lazzarini said some of the agency's staff are "unaccounted for" and "many" civilians have been injured following the Rafah attack.
"Children and women living in tented plastic makeshift shelters are among the killed," he said, adding others were "reportedly burnt to death".
"The images from last night are testament to how Rafah has turned into hell on Earth."
"The military operation in Rafah must immediately end and the flow of humanitarian assistance into Gaza must improve without further delay," he added.
The scenes coming out of #Rafah last night are harrowing.
Reports of more casualties continue to come in following an Israeli airstrike on a heavily populated area northwest of Rafah.
Children and women living in tented plastic makeshift shelters are among the killed. Many were…— Philippe Lazzarini (@UNLazzarini) May 27, 2024
The Israeli airstrike on Sunday has been described by Prime Minister Benjamin Netanyahu as a "tragic mistake".
Mr Netanyahu said the strike was not meant to cause civilian casualties.
"In Rafah, we already evacuated about one million non-combatant residents and despite our utmost effort not to harm non-combatants, something unfortunately went tragically wrong," he said.
The Israel Defence Forces had earlier said the strike was against "legitimate targets" with "precise munitions" and on the basis of "precise intelligence" - adding the incident was "under review".
Algeria has requested an urgent meeting of the United Nations Security Council to discuss the situation in Rafah.
Medics in Gaza said a further Israeli airstrike on a house in Rafah on Monday killed seven people with several others wounded.
Additional reporting: IRN
