Australia’s navy has held a bilateral exercise with the Maritime Self-Defense Force on the way to the Philippines as part of annual regional engagement activities, an Australian defense spokesperson said Wednesday, though there was no indication of a hotly anticipated trilateral drill in the South China Sea that had been expected the same day.

Japan, Australia and the U.S. were reportedly considering sending vessels laden with aircraft to the Philippines to conduct a trilateral naval drill in the disputed waterway.

It was not immediately clear why the exercise had apparently not been held.