The U.S. has reportedly told Taiwan that senior U.S. officials will not attend a defense meeting between the two countries set to open Wednesday in Hershey, Pennsylvania.

The China Times reported that senior U.S. State and Defense Department officials will not attend this year’s Taiwan-US Defense Industry Conference, the first time since the annual conference was first held in 2002.

Taiwanese media say the unexpected absence is the U.S.’s expression of its dissatisfaction about Taiwan’s role in escalating diplomatic tensions between China and Japan over a group of islands in the East China Sea.

The conference organized by the U.S.-Taiwan Business Council is a forum to discuss future defense cooperation between the two countries as well as Taiwan’s defense and national security needs and arms procurement plans.