He warned that any further aggression by Israel "would bring about the demise of the Zionist regime."
Speaking before tens of thousands of people at a memorial marking the 21st anniversary of Ayatollah Khomeini's death, Ahmadinejad said, "The Zionist regime's crimes are not perpetrated because it is strong, but because it is weak. They are crazy. They cannot control themselves."
Ahmadinejad expressed hope that more aid flotillas will make their way to Gaza in light of Monday's "achievement."
"Everyone should know that with God's help thousands of flotillas from all over the world will sail (to Gaza) with peace-lovers and give freedom and peace to mankind," he said.
Ahmadinejad warned that Israeli is planning to attack Gaza. "To make up for their past mistakes and to restore their force – the Zionists are planning another attack on Gaza," said the presidents.
The tens of thousands on hand chanted "Death to Israel".
Addressing the possibility of fresh UN sanctions aimed at curbing Iran's nuclear program, Ahmadinejad said, "We are not afraid of their (West's) fake power. With the help of God we will realize our nation's rights, even though their decisions are only on paper."
The Iranian president also warned the country's opposition against straying from the path of the founder of the Islamic Revolution.
Ahmadinejad told the crowd that those "who deviate from the Imam's path will be banished by the people." The speech comes days ahead of the opposition's mass rally planned on the anniversary of last June's disputed presidential election.
AP contributed to the report