One person has died, three people are missing, and 16 others were saved by authorities after a three-deck pontoon vessel sank off the coast of Alcatraz Island in the San Francisco Bay on Tuesday, US officials said. A dog also died in the capsizing.  

The island is home to a famous former Alcatraz federal prison, which now serves as a tourist destination. The prison was notorious for being inescapable due to the strong ocean currents and cold Pacific waters that surround it.

Alcatraz Island is about 1 mile off the shore (1.6 km) in the bay. 

Multi-pronged search effort underway  

Search and rescue teams were looking for the missing people throughout the night.

Local police and fire teams are working together along with the US Coast Guard to find survivors. Planes, boats and helicopters are being deployed in the operation.  

San Francisco fire chief Dean Crispen, in a video posted online by the city's mayor, said responders were dispatched due to a report of "a boat on fire, 600 yards of Alcatraz" Island around 3:35 p.m. local time (1035 GMT) on Tuesday.  

Although there were reports that a fire had taken place on the boat, Crispen said "we now don't have any evidence of that."  

Chrispen rescuers had found the three-deck pontoon vessel capsized and almost completely under water. The boat's motor was still running and leaking fuel. 

One dead person was found at the scene, with rescue teams making an attempt at resuscitation. 

Official: Capsized vessel was a privately-owned 'pontoon pleasure boat' 

San Francisco Fire Department Lieutenant Elias Mariano told AFP news agency that rescuers were utilizing "thermal imaging, tide prediction and modeling to help direct search efforts." 

Mariano called the capsized vessel a "pontoon pleasure boat." The boat was privately owned and it's unclear if it was heading to Alcatraz at the time of its sinking.   

Edited by: Wesley Rahn

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