NEW DELHI: Air India passengers spotted small cockroaches onboard the plane flying from San Francisco to Mumbai, and the aircraft underwent deep cleaning during the scheduled stop over at Kolkata airport on Monday early morning.

The airline said it will carry out a comprehensive probe to determine the cause of the incident and put in place measures to prevent recurrence.

The flight was operated with a Boeing 777 aircraft, according to information available on flight tracking website Flightradar24.com.

"On flight AI180 from San Francisco to Mumbai via Kolkata, two passengers were unfortunately bothered by the presence of a few small cockroaches on board. Our cabin crew, therefore, relocated the two passengers to other seats in the same cabin, where they were comfortable thereafter," an airline spokesperson said in a statement on Monday.

During the flight's scheduled fuel stop in Kolkata, the airline's ground crew conducted a deep cleaning process to address the issue and the same aircraft subsequently departed in time for Mumbai.

"Despite our regular fumigation efforts, insects can sometimes enter an aircraft during ground operations. Air India will be undertaking a comprehensive investigation to determine the source and the cause of this incident and implement measures to prevent recurrence," the spokesperson said.

The spokesperson also apologised for any inconvenience caused to the passengers.

Details about the number of passengers onboard the flight was not available.