Millions of Muslims take part in the annual Hajj pilgrimage
Saudi Arabia has warned pilgrims not to stage protests at the Hajj, a challenge to Iran which believes the event has political and spiritual dimensions.
A statement by the Saudi cabinet did not mention Iran, but followed remarks by Iran's leaders about the pilgrimage.
Supreme leader Ayatollah Ali Khamenei said Shia Muslims should show they were addressing challenges to their unity.
The Sunni-led Saudi government said political disturbances distract pilgrims and put their safety at risk.
Iranian President Mahmoud Ahmadinejad said Tehran would take "appropriate measures" if Iranian pilgrims faced any restrictions during the pilgrimage.
Meanwhile Ayatollah Khamenei called on the Saudi authorities to take action against alleged mistreatment of Shia Muslims in the country.
In 1987 Shia Muslims, mostly from Iran, clashed with Saudi Arabian police during an anti-US protest at the Hajj, resulting in the deaths of 402 people.
There have been no major Shia protests since then and Saudi forces have increased security at the event.
Hundreds of thousands of Muslims have begun to gather in the holy cities of Mecca and Medina in Saudi Arabia ahead of the peak of Hajj observance which this year falls at the end of November.
Every year about two million Muslims, both Sunnis and Shia, from around the world converge on Mecca to participate in the ceremonies.