The leaders of Spain and Ireland have called on the European Union to urgently review whether Israel is complying with its human rights obligations in Gaza.

Spanish Prime Minister Pedro Sanchez and Irish Prime Minister Leo Varadkar made the request in a joint letter to European Commission President Ursula von der Leyen on Wednesday.

The Israeli military is set for a ground offensive on Rafah at the southernmost end of the Gaza Strip, where more than 1.4 million people, including evacuees from other parts of the enclave, are taking shelter.

The letter says, "The expanded Israeli military operation in the Rafah area poses a grave and imminent threat that the international community must urgently confront."

It cites widespread concern about Israel's possible breaches of the International Humanitarian Law and asks the commission to review Israel's compliance with the EU-Israel Association Agreement, which obligates respect for human rights.

The letter adds that if Israel is found to have breached the agreement, the European Council should consider appropriate measures.

The European Union says the EU is Israel's largest trade partner.

The AFP news agency says, "The move reflects growing European frustration over the spiraling humanitarian catastrophe in Gaza, for the first time evoking the prospect of economic sanctions, albeit obliquely."