The U.S. State Department said senior diplomats of the United States and Japan reaffirmed the importance of trilateral cooperation with South Korea on Thursday.

The department issued the position in a statement after U.S. Deputy Secretary of State Wendy Sherman held talks with Japanese Vice Foreign Minister Takeo Mori.

The department said the trilateral cooperation seeks to tackle the global challenges of the 21st century. 

The statement comes a day after Mori pulled out of a planned news conference with Sherman and South Korean Vice Foreign Minister Choi Jong-kun over conflict with Seoul on the Dokdo islets. 

Mori and Choi were scheduled to appear along with Sherman after their talks on Wednesday in Washington, but only Sherman attended.

Choi told reporters that the joint news conference did not take place after Japan conveyed its intent to back out due to a visit to the South Korean islets of Dokdo by the head of the Korean National Police Agency.