Seoul, March 1 (IANS): Some offices of the Korean Medical Association (KMA), the country's largest doctors' group, were on Friday raided by police as part of an investigation into five current and former Association leaders accused of instigating a walkout by trainee doctors.

The raids, the first investigative action that police have taken since thousands of interns and resident doctors walked off the job on February 20, also came a day after the government-set deadline for the trainee doctors to return to work, Yonhap news agency reported.

Investigators from the Seoul Metropolitan Police Agency searched several offices, including that of the KMA's emergency committee and the Seoul Medical Association, to secure evidence from the mobile phones and computers of the officials.

On Tuesday, the health ministry filed a police complaint against the KMA's emergency committee chief Kim Taek-woo; two others members of the KMA leadership; a former KMA chief; and Lim Hyeon-taek, the chief of the Korean Pediatric Society.

The ministry accused them of instigating the trainee doctors' mass resignations by expressing support and providing legal assistance in the government's first legal action taken in connection with the walkout.

The investigation came as thousands of intern and resident doctors have stayed away from their jobs at general hospitals nationwide since Tuesday last week in their collective action protesting the government's plan to hike the medical school admission quota by 2,000 seats next year.

The government had given the striking interns and resident doctors until the end of Thursday to return to work or face punitive action, such as the suspension of their medical licenses.

Earlier, the police also warned that those accused in connection with the walkout would face arrest if they defy police questioning without a valid reason.