TAIPEI (Taiwan News) — The Navy will conduct “underwater investigations” for 1.5 months near the Yilan County port of Suao, reports said Saturday (June 3).

There was no explanation from the military, but speculation focused on the laying or removal of sea mines in conjunction with the annual round of Han Kuang exercises, the Liberty Times reported.

The Navy said the activities would take place from June 7 to July 21, between 8 a.m. and 5 p.m. each day. Three Navy vessels will be active in the area, so local fishing associations have been alerted to ask their members to be careful when leaving or entering the busy port of Suao.

The unit in charge of the operations is the 192nd Fleet based in Kaohsiung City, which includes the country’s minesweeping force. The exercise could be interpreted as preparations to seal off the harbor due to an attack from China, according to the Liberty Times.

There were also plans to order a second group of four ships, but the military has not prepared a budget for the deployment yet.