SACRAMENTO (CBS SF) – A Southwest Airlines flight from Sacramento to Denver was diverted to Oakland International Airport Sunday evening because of a pressurization issue, a Southwest spokesman said.

Flight 1665 from Sacramento International Airport landed safely in Oakland at about 5:15 p.m., airport spokeswoman Keonnis Taylor said.

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The flight had 133 passengers on board.

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Southwest Airlines officials had a new aircraft waiting for the passengers to take them to Denver.

The passengers will get to Denver about three hours behind schedule, Southwest Airlines spokesman Dan Landson said.

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The aircraft that left Sacramento will stay out of service until it is checked.