Saudi Arabia has warned that it will not allow anyone to undermine security during this year's Hajj pilgrimage.
Many Muslims save for years to go to Mecca for the Hajj pilgrimage
The first of more than two million pilgrims have already arrived ahead of the Hajj, which peaks next month.
Crown Prince Abdullah said the pilgrims must concentrate on their religious duties and avoid activities that would disturb the occasion.
The Hajj is one of the five pillars of Islam. Muslims are expected to make the trip at least once, if they can.
The huge numbers attending the annual pilgrimage to Mecca have long posed a challenge to the Saudi authorities.
Stampedes have claimed hundreds of lives during the ritual in recent years.
This year, for the first time, foreign airlines are being allowed to fly pilgrims to the holy city of Medina, in a move which it is hoped will relieve pressure on the main Hajj airport at Jeddah.
It is anticipated that Medina will receive up to 30 Hajj flights every day until the start of the pilgrimage at the end of January.