The United States and its Asian allies flew dozens of fighter jets in the midst of North Korean tensions.

The United States and its Asian allies flew dozens of fighter jets over waters surrounding the Korean Peninsula on Tuesday in a show of force as their diplomats discussed a coordinated response to a possibly imminent North Korean nuclear test.

The flights came as US Deputy Secretary of State Wendy Sherman travelled to Seoul for discussions with South Korea and Japanese officials over the gathering North Korean threat and warned of a “swift and forceful” counterresponse if the North proceeds with a nuclear test explosion, which would be its first in nearly five years.