The South Korean Army has launched an investigation into allegations that a senior male cadet sexually assaulted a junior female officer cadet under the influence of alcohol on campus during a festival last week, military officials said Wednesday.

Last Wednesday, about 30 students and professors at the Korea Military Academy had lunch and drank alcohol after a sports event earlier in the day to celebrate Cadet Day.

After a female sophomore drank too much and kept vomiting, the senior cadet brought her to his room and reportedly assaulted her, according to Army officials.

It is the first time a sexual abuse case involving cadets has taken place on campus since women were admitted to the elite military academy in Seoul in 1998.

The military police have arrested the male cadet and authorities have set up a joint investigation team to look into the incident, officials said.

The Army expressed regret over the incident and vowed to sternly punish those involved and prepare sexual assault prevention measures.

"A special team is thoroughly investigating the case immediately after it happened," the Army's spokesman said in a statement. "We will reinforce education programs and supplement related regulations."

Drinking is prohibited at the military academy, but students have been allowed to drink occasionally during official events under the guidance of professors and senior officers since 2011.

The sexual assault case has been kept secret for a week by the Army and the military academy, sparking suspicions that they may have been trying to cover up the incident. Officials, however, said the decision was made to protect the victim.

"The Army takes the matter seriously and officials have investigated the case in secrecy due to concern over the disclosure of the female cadet's identity and additional damage to the victim," a senior Army official said. (Yonhap News)