The lockdown on Qatif, a Shia-majority region and home to around 500,000 people, is the first action of its kind across the Gulf that has confirmed more than 230 coronavirus cases — most of them people returning from pilgrimages to Iran.
“Given that all 11 recorded positive cases of the new coronavirus are from Qatif... it has been decided... to temporarily suspend entry and exit from Qatif,” the interior ministry said in a statement.
The lockdown comes as Saudi Arabia announced it was closing all public and private universities and schools across the country from Monday until further notice.
The country has also suspended Umrah over fears of the disease spreading to Makkah and Madina.
The unprecedented Umrah suspension has raised uncertainty over Haj, scheduled for the end of July Except for essential services such as pharmacies and gas stations, work will stop in all government and private institutions in Qatif, the statement added.
Although the ministry said the lockdown was temporary, it risks fuelling resentment in the flashpoint region whose residents have long accused the government of discrimination, a charge Riyadh denies.
Saudi Arabia’s Eastern Province — which includes Qatif — has seen bouts of unrest since 2011 when protesters emboldened by that year’s Arab uprisings took to the streets.
Saudi Arabia has condemned Iran for allowing its citizens entry without stamping their passports.
The Saudi government has reminded its nationals of a standing ban on travel to Iran, as the two countries are locked in a battle for regional supremacy.