"General Mattis plans to visit Japan and Korea in early February," Pentagon spokesman Gary Ross said.
In choosing Japan and South Korea for his first overseas visit, Mattis is singling out two longstanding allies worried about the direction of US policy in their region under President Donald Trump.
During the campaign, Trump threatened to withdraw US forces from the two countries if they did not step up their financial support.
Tensions are also rising with China over its moves to assert sovereignty in disputed areas of the South China Sea, and over North Korean threats to test an intercontinental ballistic missile capable of striking the US mainland.
The agreement was signed by 12 countries bordering the Pacific. In addition to the United States, signers included Australia, Brunei, Canada, Chile, Japan, Malaysia, Mexico, New Zealand, Peru, Singapore and Vietnam.
Disclaimer: No Business Standard Journalist was involved in creation of this content