Three dozen soldiers and officers at an Army unit in the northern city of Pocheon have tested positive for the new coronavirus, the defense ministry said Monday.

Three of them were first confirmed to be infected with COVID-19 on Sunday before all other members of the unit went through virus tests and 33 of them tested positive, according to the ministry.

The military and health authorities are tracing their routes of infection, and the exact cause has yet to be identified. But one infected officer was found to have visited Seoul late last month, according to officials.

"We are tracing where he has been as part of our investigation into the infection route," a ministry official said. "Except for the official, no one in the unit has gone on vacation since September."

The defense ministry imposed a ban on service members' vacations and restrictions on their off-installation outings since mid-August to stem the spread of the new coronavirus. The restrictions are supposed to be in place until Oct. 11 in line with the government's social distancing guidance.

But vacations are allowed for new recruits and those who have not traveled off-base for a long period of time based on decisions by their leadership.

In the wake of the cluster infection, the defense ministry on Monday imposed a complete ban on off-base trips for all service members stationed in Pocheon.

Defense Minister Suh Wook plans to hold an emergency meeting involving major military commanders later in the day to discuss measures to prevent the virus from spreading further into the barracks, according to the ministry.

So far, the military reported 148 COVID-19 patients. Currently, 264 service members are in isolation according to the health authorities' guidelines, and 253 others are quarantined as a preventive step in accordance with the military's tougher guidance. (Yonhap)