The United States has finalized a 20-year extension to its agreement on ties with the strategic Marshall Islands and expects to sign the $2.3 billion deal on Monday, chief U.S. negotiator with the Pacific island nation Joseph Yun told Reuters.

The Republic of the Marshall Islands (RMI) is one of three sprawling but sparsely populated nations that have U.S. ties governed by so-called Compacts of Free Association (COFAs), under which Washington is responsible for their defense and provides economic assistance, while gaining exclusive military access to strategic swaths of ocean.

After decades of relative neglect, the nations have found themselves at the center of a U.S. battle for influence with China in the Northern Pacific and the Biden administration agreed new deals with the two other states, Palau and Micronesia, earlier this year.