Alcatraz the historic US island prison off San Francisco, opened up for a limited number of indoor tours, which had been off-limits for more than a year due to the pandemic.

Face masks and social distancing are still required at the island, which once housed inmates such as Al Capone and George “Machine Gun” Kelly.

Ferries to Alcatraz are operating at 25% capacity, carrying about 150 passengers instead of the usual 600.

Access to the infamous cell house in California will also be limited only to visitors who sign up for the audio tour in advance.

Safety modifications have been made throughout the island including social distancing markers, increased cleanings and hand sanitising stations.

Food service will not be available on the ferries or on the island.

In August, the popular tourist destination opened to an outdoor-only experience, to reduce the risk of spreading Covid-19.

Alcatraz usually hosts up to 5,000 tourists a day.

For now, that number will be reduced to about a thousand.