South Korean police on Monday commenced an investigation into an anonymous online post urging trainee doctors to delete hospital files before resigning, as part of collective action by local physicians in protest of the government plan to increase the enrollment quota for medical schools.

Seoul Gangnam Police Station said it was trying to track down the person who wrote the post, based on a tip-off it received around 1:30 a.m. this morning. The post is believed to have first been uploaded on Mediestaff, an online community used by doctors and medical students.

The post urged doctors to delete files from the shared folders of their medical offices, adding instructions to make it as hard as possible for other medics to fill in for them. The person also urged doctors not to leave bags behind to avoid uncertainty over whether they were resigning, and make it impossible for physician assistants to carry out their medical duties in their place.

The post has led to criticism from the public that such calls pay no regard to patients' lives.

The trainee doctors at five major hospitals in Seoul -- Asan Medical Center, Samsung Medical Center, Severance Hospital, Seoul National University Hospital and Seoul St. Mary's Hospital -- submitted letters of resignation in masse on Monday. They are set to partake in a mass walk-out Tuesday, according to the Korea Intern Resident Association.

South Korean government has vowed strict actions against any collective action by doctors that threatens the safety of their patients, and the Ministry of Health and Welfare on Monday ordered trainee doctors to keep providing treatments.

Doctors have been at loggerheads with the government over its plan to increase next year's medical school enrollment quota by 2,000. The number of places has been held at the current 3,058 since 2006. The move aims to address the shortage of doctors, particularly in essential medical fields.

The most recent figures from the Organization for Economic Cooperation and Development shows that South Korea has 2.6 practicing doctors per 1,000 people, lower than the OECD average of 3.7 and of any member state bar Mexico which has 2.5.