Taiwan is strengthening its ability to move troops swiftly in case China suddenly turns one of its frequent drills around the island into an attack, Defence Minister Wellington Koo said on Wednesday,

Taiwan is in a complicated position in the relationship between China and the U.S., one that is already fraught over issues such as trade, technology transfers and human rights. Beijing has pledged to bring Taiwan under its control someday, by force if needed.

In an echo of long-held U.S. warnings, Taiwan for the first time identified 2027 as the year a potential Chinese invasion of the democratic island could be unleashed.