Saudi Arabia's interior minister warned Muslim pilgrims on Wednesday against exploiting next week's annual hajj for political purposes.
"The Saudi government urges all pilgrims to perform this ritual away from any action that could put their safety at risk," the official SPA news agency quoted Interior Minister Prince Mohammed bin Nayef as saying.
"The safety of pilgrims requires us to take seriously any expected developments," he added, noting that his country was the scene of a "wave of terrorism that did not exclude the holy sites" in the early 2000s.
That was a reference to Al-Qaeda attacks that rocked the kingdom between 2003 and 2006, prompting a relentless crackdown by authorities, which he oversaw.
The minister did not say what developments might be expected, but there have been reports that members of Egypt's Muslim Brotherhood have been urging pilgrims to express their support for the group after Islamist president Mohamed Morsi was ousted in July.
The kingdom strongly backed Morsi's ouster, immediately pledging millions in aid to the new government.
And in an August video message, a top Saudi member of Al-Qaeda, Ibrahim al-Rubaish, criticised King Abdullah's support for the Egyptian army's actions.
Saudi authorities usually warn pilgrims from carrying out any actions of political nature.
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This year Riyadh expects about two million pilgrims, after the ultra-conservative kingdom announced a crackdown on illegal pilgrims and imposed restrictions to cut foreigners by 20 percent and Saudis by 50 percent.
The pilgrimage starts on Sunday and ends on October 18.
Monday marks the most important day, when all pilgrims assemble at Mount Arafat, just outside Mecca, for the peak of the hajj.
The kingdom has mobilised 95,000 members of the security forces, in addition to troops supporting the defence ministry, the national guard and intelligence, according to the minister.
He also said the king has approved the creation of a 40,000-strong special force to secure the pilgrimage.
Iranian pilgrims annually stage a "repudiation of polytheists" rally -- a ritual promoted by the late Islamic republic's revolutionary leader Ayatollah Ruhollah Khomeini to denounce the West and Israel.
In 1987, police attempts to stifle the demonstration that year sparked clashes in which 402 people died, including 275 Iranians.
Iranian pilgrims have since held their rallies in tents without provoking clashes with security forces.
Though marred in the past by deadly floods, stampedes and fires, the hajj has become nearly incident-free in recent years because of multi-billion dollar projects to improve security.