Iran's president has warned that foreign forces are threatening the security of the Gulf, after the US said it was deploying troops to the region.
Hassan Rouhani said foreign forces had always brought "pain and misery" and should not be used in an "arms race".
The US is sending more troops to Saudi Arabia after an attack on Saudi oil facilities both nations blame on Iran.
Mr 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.
The latest flashpoint was caused by drone and missile attacks on the Saudi oil facilities at Abqaiq and Khurais on 14 September.
Yemen's Iran-aligned Houthi rebels said they had carried out the attacks, but both the US and its ally Saudi Arabia - Iran's main regional rival - said Iran was behind them, something Tehran has strongly denied.-BBC