Known as the Okinawa Consolidation Plan, the pact outlines how Marine Corps units stationed on the island will hand over the various bases and installations to the Japanese government, according to the DOD
While Searight did not provide specifics on the handover timeline, she did note Washington and Tokyo were aiming to have a majority of the Marine Corps installations in Okinawa transitioned to Japan "no sooner than" fiscal 2020.
Once complete, those U.S. forces in Okinawa will be transitioned to other areas in the Pacific, such as Guam and the new Marine Corps base in Darwin, Australia.
"United States will consolidate our forces over time and reduce our impact on the most populated parts of Okinawa," Defense Secretary Chuck Hagel said in a statement Friday.
Despite the deal, Congress is threatening to block funding for the deal until the DOD can explain how it fits into the White House's new national security strategy in the Pacific and defense spending plan in Washington.
Senate lawmakers blocked funding for the transfer in the fiscal 2013 Defense Authorization Act.
Senate Armed Services Committee Chairman Carl Levin (D-Mich.) and ranking member John McCain (R-Ariz.), among others, argue the department has been intentionally vague on how it plans to pay for the Okinawa shift.
"Based on the information we have received about this emerging agreement, we have many questions that have not been fully addressed," according to a letter by the lawmakers to the Pentagon last April.
Navy and Marine Corps say a cost review on the Okinawa plan is still ongoing.
DOD leaders, led by Chairman of the Joint Chiefs of Staff Gen. Martin Dempsey, are currently reviewing the overall Pacific-centric national security plan unveiled last February.
That said, Hagel noted the new Okinawa plan will reinforce confidence among U.S. allies in the Pacific at a time when tensions in the region are at an all-time high.
"Now more than ever it is essential that the United States maintain a geographically distributed and sustainable force throughout Asia that can provide for the protection of Japan and our other allies, and U.S. interests," Hagel said.
The game of military one-upmanship between North Korea, the United States and its Pacific allies are threatening to bring the region to the brink of war.
On Wednesday, North Korean dictator Kim Jong Un reportedly gave approval for a nuclear strike against Guam, Hawaii and the U.S. mainland.
That same day, the DOD ordered a battery of ballistic missile defense systems to Guam and deployed two Navy destroyers armed with similar anti-missile weapons to the Western Pacific.
North Korea has its long-range artillery and rocket units aimed at Seoul on full alert, and it eliminated a military hotline with South Korea. Pyongyang also officially terminated the 1953 armistice with South Korea that ended the Korean War earlier this month.
The escalating crisis with North Korea was prompted by Pyongyang's recent, repeated violations of United Nations sanctions on the country's nuclear and long-range missile tests.
— Updated at 11:36 a.m.