After the United States said that it was deploying troops to the region, Iran's president has warned that foreign forces are threatening the security of the Gulf.
Hassan Rouhani said foreign forces had always brought "pain and misery" and should not be used in an "arms race".
The United States is sending more troops to Saudi Arabia after an attack on Saudi oil facilities both nations blame on Iran.
Rouhani also said Iran would present a new Gulf peace initiative at the United Nations in the coming days.
This year has seen continuing tension between the US and Iran, following President Donald Trump's abandonment of a deal aimed at limiting Iran's nuclear activities in return for the easing of sanctions.