An extra 5000 police have been deployed in Makka for the last 10 days of Ramadan, which runs until around 25 November, a particularly favourable period for Muslim pilgrims visiting the birthplace of Islam, said officials this week.
“This year has witnessed an increase in precautions and security preparations," an Interior Ministry official told the Saudi Gazette. "The government is exerting extreme caution.”
Last week Saudi authorities said they had foiled a plot to target pilgrims after two separate clashes in Makka. Four alleged fighters were killed and police said they had found tonnes of explosives and rocket-propelled grenade launchers.
Security forces also claimed they found booby-trapped copies of Islam's holy book, the Quran, and water bottles stuffed with explosives, a Saudi newspaper reported this week.
“I do think Makka is a big concern for the authorities," said one Western diplomat.
As well as Ramadan pilgrims, Makka will host two million Muslims in February for the main Haj pilgrimage.
Officials say the extra precautions were planned long before last week's raids or Sunday's bombing at a residential compound in Riyadh, which killed at least 18 people, mainly Arabs.
Analysts said the attack was aimed at undermining Saudi security and challenging the ruling family.
The latest bombings in Riyadh
shocked the Arab world
Fighters who carried out that attack used a vehicle painted with military markings to get past a national guard checkpoint.
The Makka reinforcements will come instead from police and civil defence forces, said officials.
On 12 May, 35 people died in triple human bombings at residential compounds in Riyadh. Since then, Saudi authorities have cracked down on alleged fighters and gun clashes are increasing.
Makka strike doubts
Some analysts doubt alleged fighters plan to strike Makka itself, as this would alienate all but a tiny hard core of supporters.
“I wouldn't rule anything out, particularly after the killing of Arabs and Muslims in the Riyadh compound, but I don't think the arrests and shoot-outs in Makka necessarily mean the militants want to attack pilgrims," said Neil Patrick of the Economist Intelligence Unit in London
In 1979, after Iran's Islamic revolution sent tremors across the Gulf, nearly 500 people stormed Makka's grand mosque. They were thrown out after fierce fighting and a siege in which 300 people, mainly the rebels, were killed.
Bolstering the monarchy's religious legitimacy, King Fahd later took the title Custodian of the Two Holy Mosques. "Clearly his role as custodian would be in question were the Saudis to allow anything to happen in Makka," said the Western diplomat.
Fahd arrived in Makka on Thursday to spend the rest of Ramadan in the holy city, reported Saudi media.