He made the comments during his meeting with Russian President Vladimir Putin in Moscow, where the two leaders discussed the developments in the Middle East.
"The Iranians declare their intention to attack us," Netanyahu's office cited him as saying in a statement.
Iran is trying to transfer forces and deadly weapons to Syria with the "explicit goal" of attacking Israel as part of their strategy to destroy it, he added.
Netanyahu also presented his perspectives on issues including Iran's secret nuclear archive obtained by Israel's spy agency and the rising tension between the two countries.
"These matters were presented in a direct and forthright manner," and "are very important to Israel's security at all times and especially at this time," he explained.
Earlier in the day, Netanyahu, along with Putin and Serb President Aleksandar Vucic, attended the parade in Red Square commemorating the 73rd anniversary of the victory over Nazi Germany in World War II.