"There will be a trial of the Zionists' accomplices and the U.S. and its allies," Mahmoud Ahmadinejad told journalists.
He also said Israel had been defeated in the first week of its invasion of Gaza, "and the further it continues its crimes, the more it will blacken its reputation."
Ahmadinejad also claimed that the UN Security Council was unable to adequately deal with modern challenges and threats.
"The UN Security Council is only a tool in the hands of the U.S. and Britain, who implement their criminal goals through it. This body is unable to ensure security on the planet," the Iranian president said.
Ahmadinejad commented that the Security Council took "unilateral" decisions in favor of Israel during its armed conflicts with Lebanon and the Palestinian resistance.
Ahmadinejad also said it would be "a good idea" to use an embargo on oil supplies to Tel Aviv's allies.
Over the 20 days of the Israeli military offensive in the Gaza Strip, more than 1,050 Palestinians have been killed, most of them civilians, according to the Palestinian health ministry. Thirteen Israelis have lost their lives, nine of whom were military personnel.