Correction: A previous version of this story incorrectly reported the number of people being asked to resign.

A purge of political appointees may be underway at NJ Transit, with Gov.-elect Phil Murphy asking for the resignation of a group of senior staff members, NJ Advance Media has learned.

The requests were made in a letter sent to NJ Transit Executive Director Steven Santoro from Murphy's transition team. The letter named about 20 people, who have until the end of the week to submit their resignation letters.

They will be allowed to continue working in their current jobs unless the transition team or Murphy's nominee for transportation commissioner tells them otherwise, the letter said.

Murphy called NJ Transit a "national disgrace" when he nominated Diane Gutierrez-Scaccetti for transportation commissioner last month. Murphy made reforming NJ Transit a campaign issue and said the agency must be turned "upside down" and shaken up to "make it right again."

The letter provided to NJ Advance Media did not include a list of names, which a source said included about 20 people.

Similar letters have gone out to other state departments, said Dan Bryan, a spokesman for Murphy.

"Our office has sent a letter to various state agencies to discuss the transition to Governor-elect Murphy's administration, which included employment matters," Bryan said. "This is common practice for incoming administrations, and the effort is being made to be as accommodating as possible to current staff. We cannot comment on specific names."

The letter comes less than a week after Santoro announced his resignation, effective in April. NJ Turnpike Authority Executive Director Joe Mrozek resigned in December and said he was doing so to allow the new administration to make an appointment.

Larry Higgs may be reached at lhiggs@njadvancemedia.com. Follow him on Twitter @commutinglarry. Find NJ.com on Facebook.