Iran's supreme leader Ayatollah Ali Khamenei accused on Tuesday of Israel of committing "genocide" in Gaza Strip.

"What Israeli authorities are doing (in Gaza) is genocide and a big historical disaster," Khamenei said while addressing a crowd gathered to celebrate the festival of Eid al-Fitr, which marks the end of fasting during the Muslim holy month of Ramadan.

The international community should demand punishment for the crimes committed, Khamenei said, stressing Israel's supporters should also be punished.

"The first and foremost issue of the Islamic world and, perhaps, humanity today is Gaza," he said, adding that "a rabid dog and a rapacious wolf have attacked the oppressed people and the world should react to this."

"The resistance of Palestinians in Gaza," living under blockade and deprived of water and power supplies, shows "the power of a nation" and this is "a big lesson," he added.

The recent developments in Gaza show that the enemy is " regretful" and caught in a dilemma, so it seeks European and the U. S. help to "impose cease-fire on the Gazans," Khamenei said.

On Tuesday, Iran's Foreign Minister, Mohammad-Javad Zarif, reiterated his earlier stance saying that any cease-fire in the embattled coastal enclave should meet the demands of the Palestinians in Gaza, which include the removal of the years of siege on the strip.

"The Zionist regime has taken advantage of the situation created under the siege and launched a full scale onslaught in Gaza," Zarif was quoted as saying by semi-official Fars news agency.

Iranian Deputy Foreign Minister Morteza Sarmadi reiterated Zarif's position on Tuesday, while stressing the humanitarian crisis in Gaza during a meeting with the outgoing Italy ambassador to Tehran Luca Giansanti.

The Iranian supreme leader rejected on Tuesday international calls to disarm the Islamic militants in Gaza, saying that "the U. S. president has issued a fatwa (decree) that the resistance should be disarmed so that (militants) cannot respond to all the ( Israeli) crimes, however ... the world and the Islamic world, in particular, should help supply the Palestinian people."

Khamenei said a week ago that "armed resistance" was the only possible response to the atrocities of Israel against Palestinians.

"We believe that the (Palestinians) in the West Bank should also be armed like in Gaza," he said.

On Tuesday, Iranian President Hassan Rouhani called for Muslim countries to ship aid to Gaza, official IRNA news agency reported.

Iran's defense minister asked Muslims to stand united in the face of Israeli "brutalities" against the Palestinians, Press TV reported on Tuesday.

Muslim unity and solidarity as well as complete support of the Muslim countries would contribute to the realization of the Palestinian cause, which is the liberation of the holy al-Quds ( Jerusalem), Brigadier General Hossein Dehqan said in a congratulatory message to his counterparts in Islamic states on the occasion of Eid al- Fitr.

Also on Tuesday, a total of 24 Palestinians were killed in three separate airstrikes against Gaza, medics and witnesses said.

Ashraf al-Qedra, Gaza health ministry spokesman, told reporters that tanks shelling on a house in Jabalia refugee camp in northern Gaza Strip killed 16 Palestinians and wounded dozens.

He said that most of the casualties, dead and wounded, are women and children, adding that another woman was killed in Israeli tanks shelling on Zeitoon neighborhood in southern Gaza city.

Three more were killed in an Israeli airstrike on a house in Rafah town in southern Gaza Strip, he said, adding that four bodies were pulled out from under the rubble of a destroyed house in the town of Khan Younis.

"Today is the bloodiest day ever since the beginning of the Israeli war on the Gaza Strip that has been going on the Gaza Strip for 22 days," said al-Qedra, adding "we are receiving unprecedented numbers of dead and wounded."

In a press statement, he said as Israel intensified its air, ground and sea strikes overnight and on Tuesday all over the Gaza Strip, at least 100 Palestinians were killed and more than 500 wounded.

On July 8, Israel launched a massive offensive on the enclave, claiming that it aimed to stop incessant rocket fire from Gaza that targeted its southern territories. It later said that the purpose of the offensive is to destroy the underground network of cross-border tunnels, which enable militants to slip into Israel.

The devastating campaign has claimed the lives of at least 1, 130 people in Gaza, most of them were civilians, with more than 6, 700 others wounded. Meanwhile, 53 Israeli soldiers and three civilians were killed.