New Delhi, Sep 10 - Civil aviation authorities Thursday asked all airlines to restrain from raising fares when the Jet Airlines pilots are on strike.

The Directorate General of Civil Aviation (DGCA) has written to all airlines not to charge higher fares and limit their charges to those prevailing last week, a civil aviation ministry spokesperson said.

Passengers, already facing trouble with the cancellation of Jet flights, have complained that some airlines have arbitrarily hiked their fares.