Iran's foreign ministry said it believes it is "necessary" to retaliate against Israel for the assassination of Hamas leader Ismail Haniyeh.

A spokesperson for the foreign ministry, Nasser Kanaani, said while Iran was not seeking to escalate tensions, it views punishment as a "necessary" response to the killing of Haniyeh in Tehran and to prevent further instability, according to Reuters and The Guardian.

Nobody has claimed responsibility for the attack on Haniyeh, but Iran and Hamas have accused Israel of carrying out the strike.

IRAN REJECTS PLEAS FROM US, ARABS TO SHOW RESTRAINT IN RESPONSE TO ASSASSINATION OF HAMAS LEADER

This comes after Iran rejected calls by the U.S. and Arabs to moderate its response to the killing of Haniyeh, with the U.S. warning that any significant strike would illicit a response and that new Iranian President Masoud Pezeshkian's efforts to improve engagement with the West would be better received if Iran shows restraint, The Wall Street Journal reported.

The U.S. also said it was urging Israel to deescalate tensions.

Iranian leaders told Arab diplomats on Saturday that it does not matter to them if their retaliation leads to a war.

Israel said it was prepared to defend against and respond to any retaliatory strike.

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"Israel is now in a multifront war against the Iranian axis of evil," Israeli Prime Minister Benjamin Netanyahu said on Sunday. "We are ready for any scenario, either defensive or offensive. I repeat to our enemies: We will respond and exact a heavy price for any act of aggression against us, from any arena."

Haniyeh, who was in Tehran to attend the inauguration of Iran's new president, was killed by a bomb while staying in an Islamic Revolutionary Guard Corps guesthouse, according to The Wall Street Journal, although Iran and Hamas have disputed that a bomb killed Haniyeh, claiming instead that he was struck by a missile.

Israel has not publicly commented on the killing.

Reuters contributed to this report.