The leader of the revolution and the Islamic Republic of Iran's aide, Ali Shamkhani sits in a meeting in Tehran, Iran on June, 12, 2021. (AP)

Advisor to the Leader of Iran Sayyed Ali Khamenei, Ali Shamkhani, said on Saturday that preparations are already in place for a "severe and crushing" retaliation against "Israel" following the assassination of Hamas chief Ismail Haniyeh in Tehran.

“Legal, diplomatic & media processes laid the ground for severely punishing a regime that only understands the language of force," Shamkhani wrote in a post published on X on Saturday.

The only goal of #Israel in killing worshippers at #Tabeen School in Gaza,assassinating martyr #Haniyeh in #Iran is warmongering & derailing the truce talks. Legal,diplomatic & media processes laid the ground for severely punishing a regime that only understands language of force
— علی شمخانی (@alishamkhani_ir) August 10, 2024

Haniyeh, who was in Tehran to attend the swearing-in ceremony of Iran's newly-elected President Masoud Pezeshkian, was martyred along with his bodyguard in an early morning attack on July 31.

Sayyed Khamenei issued a stern warning to "Israel", pledging a "harsh response" for Haniyeh's assassination and asserting that avenging the death of the Palestinian Resistance leader is the Islamic Republic's duty. “The criminal and terrorist Zionist regime martyred our dear guest in our homeland and left us bereaved, but it also set the ground for a harsh punishment for itself,” he added.

Shamkhani also condemned the Israeli strike on a school in Gaza City that was housing displaced people, which resulted in the martyrdom of over 100 Palestinians and injuries to dozens more early on Saturday.

The senior Iranian official argued that “The only goal of Israel in killing worshipers at the al-Tabin School in Gaza and assassinating martyr Haniyeh in Iran is warmongering & derailing truce talks".

'Iran won't back down'

Earlier last week, Iran rejected American and Arab efforts to tone down its response to the Israeli assassination of Hamas Political Bureau chief Ismail Haniyeh in Tehran, The Wall Street Journal reported on August 4.

The WSJ cited people familiar with the talks as saying that Tehran informed Arab diplomats on Saturday that it is unconcerned if its response to the Israeli assassination leads to the outbreak of war. According to the sources, the United States requested Europe and other allied governments to convey a message to Iran urging it to avoid escalation, warning that any major strike could provoke a response.

The Wall Street Journal pointed out that "Iran has refused to provide detailed warnings that would help mitigate the impact of any strike."

In an earlier statement, Al Mayadeen's correspondent in Tehran cited an informed Iranian source as saying that Iran considers Haniyeh's assassination to be one of its red lines that was crossed, "regardless of the details of the operation," indicating that it will handle the response accordingly.

That is why "Iran will respond in a way that crosses the red lines set by the Israeli occupation," the informed source affirmed.