"The kingdom backs and welcomes the firm strategy on Iran and its aggressive policy that was announced by US President Donald Trump," the official Saudi Press Agency said in a statement.
The Sunni monarchy in Saudi Arabia has for years accused Shiite Iran of "destabilising" the Arab world. The region's two powerhouses also support opposite sides in the wars in Syria and Yemen.
The two countries severed diplomatic ties in January 2016 after Iranians stormed Saudi Arabia's embassy and consulate in response to the execution of a prominent Shiite cleric.
In today's statement, Riyadh said it would continue working with the United States and other world powers to "deal with the dangers represented by Iran's policy on all levels".