Islamic countries must close ranks and respond to Israel's deadly attacks on the Gaza Strip, Iran's Defence Minister Ahmad Vahidi said on Saturday.

"Putting an end to the Zionist (Israeli) regime's crimes is only possible through a united, revolutionary retaliation by the Muslim world," Vahidi said in remarks carried by the official IRNA news agency.

Israel is "massacring the oppressed Palestinian people, including women and children" and its strikes amount to a "clear example of war crimes," the defence minister charged.

The Jewish state launched a major air offensive on Gaza on Wednesday with a strike that killed the top military commander of the Islamist movement Hamas which rules the territory.

Foreign Minister Ali Akbar Salehi, whose country is a key backer of Hamas, on Thursday urged the United Nations and European Union to pressure Israel to halt its offensive, saying the security of the Middle East was at stake.

Salehi has also announced his readiness to visit Gaza.

And speaking to exiled Hamas chief Khaled Meshaal on the telephone, Salehi said Iran was ready to send "medical and medicinal aids" to Gaza, the official IRNA news agency reported.

On Saturday, media reports said Iran was preparing to dispatch a parliamentary delegation to the Palestinian territory.

The foreign ministry is "talking with Egyptian officials to facilitate the visit through Rafah," a terminal at Gaza's southwestern border with Egypt, according to MP Mansour Haqiqatpour.

Previous attempts by Iran's hardline parliament to dispatch a team into Gaza failed during the rule of former Egyptian president Hosni Mubarak.

Palestinian medics said on Saturday that 38 Gazans have been killed since Israel launched the aerial campaign, while Israel's army says Palestinian militants have fired more than 580 rockets over the border.

Three Israelis have been killed and 13 injured by the rocket fire.