Palestinian militants from the Iran-backed Islamist group Hamas, which controls the Gaza strip, penetrated Israel at dawn on Saturday under the cover of a massive rocket barrage.
Almost 1,000 people have been killed in the conflict so far, with Israel reporting more than 600 lives lost and Gaza’s health ministry putting its toll at 370 dead.
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“Iran supports the legitimate defence of the Palestinian nation,” Raisi said, quoted by state television.
“The Zionist regime (Israel) and its supporters are responsible for endangering the security of nations in the region, and they must be held accountable in this matter.”
He urged Muslim governments to “support the Palestinian nation” while praising “resistance” efforts by Hamas and Islamic Jihad as well as in countries including Syria, Lebanon, and Iraq.
Raisi had spoken earlier with leaders of Hamas and Islamic Jihad, official media said.
State news agency IRNA said he had “discussed the developments in Palestine” in separate phone calls with Islamic Jihad secretary general Ziyad al-Nakhalah and Hamas chief Ismail Haniyeh.
Pro-Palestinian gatherings
The Islamic Republic hosted talks with leaders of Hamas and Islamic Jihad in June.
At the time, Raisi said Israel was seeking to normalise ties with more Arab and Muslim countries “to discourage young Palestinians from (seeking to) liberate the occupied territories”, according to the presidency.
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On Saturday, hundreds of people gathered in major cities of Iran, including in Tehran’s Palestine Square, carrying the Palestinian flag.
They also held pictures of Iranian general Qasem Soleimani, who was assassinated in a US drone attack in Baghdad in 2020 after overseeing the Revolutionary Guards’ foreign operations for more than a decade.
Billboards celebrating the offensive Hamas has dubbed “Al-Aqsa Flood” were installed in the capital, including one declaring: “The great liberation operation has begun”.
Crowds in some cities set off fireworks and torched Israeli flags.
Others marched in Palestinian colours while motorists honked their horns in jubilation, as seen in video footage from IRNA.
Iran does not recognise Israel and has made support for the Palestinian cause a centrepiece of its foreign policy since the 1979 Islamic Revolution.
The bitter rivals have engaged in a shadow war for years, with Iran accusing Israel of a series of sabotage attacks and assassinations targeting its nuclear programme.
The United States and Israel have previously accused Iran of using drones and missiles to attack US forces and Israel-linked ships in the Gulf.