A Palestinian woman stands in a classroom doorway at a United Nations run school acting as a shelter for residents who fled their homes during an Israeli ground operation, in Jabaliya in the northern Gaza Strip July 29, 2014.  [Photo/Agencies]

TEHRAN - Israel has committed "genocide" in Gaza Strip, Iran's supreme leader Ayatollah Ali Khamenei said on Tuesday.

"What Israeli authorities are doing (in Gaza) today is a genocide and a big historical disaster," Khamenei said when addressing a huge crowd gathered to mark the festival of Eid al- Fitr at the end of fasting Muslim month of Ramadan.

The nations and the world peacemakers should demand the punishment of those who committed these crimes and those who were their supporters, Khamenei said, stressing that the passage of time should not affect this demand.

"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, who are 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" about what it had done and it is strangled in a dilemma, so it seeks European and the US help to "impose cease-fire on the Gazans," Kamenei said.

Earlier, senior Iranian officials said that any cease-fire in the war-ridden coastal enclave should meet the demands of the Palestinians in Gaza, which is an urge for the lift of years-long siege on Gaza Strip.

The Iranian leader rejected calls for disarming the Islamic militants in Gaza, saying that "the US president has issued a fatwa (decree) that the resistance should be disarmed so that they (militants) cannot respond to all the crimes (by Israel in Gaza), however... the world and the Islamic world, in particular, should help supply the Palestinian people (with arms)."

Khamenei said a week ago that the "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... So that the agonies of the Palestinian people could be lessened as they get powerful and their enemy becomes weaker," he said.

Israel has embarked on a massive offensive on Hamas-ruled Gaza on July 8, saying it was aimed at stopping the rocket fire from the southern Palestinian enclave. It later said that the purpose of the offensive is to destruct the underground network of cross- border tunnels, which enable militants to slip into Israel.

The devastating campaign claimed the lives of at least 1,100 people in Gaza, most of them were civilians, and killed 53 Israeli soldiers and three Israeli civilians.