WASHINGTON — Japan will officially increase its order of F-35 joint strike fighters, including procurement of the F-35B model — making the Pacific nation the second-largest buyer of the Lockheed Martin-made jet.

Tokyo previously planned to procure 42 F-35A models. However, a source close to the program confirmed that Japan will be adding 63 F-35A models, as well as 42 F-35B models, for a total of 147 F-35 fighters.

The announcement, anticipated for weeks, was rolled out as part of Japan’s new defense plan Tuesday.

The package would make Japan second only to the United States in terms of procured F-35s, with the United Kingdom (138 total fighters) now third. Japan also becomes the fourth user of the "B" model, joining the U.S. Marine Corps, the United Kingdom’s Royal Air Force and the Italian Navy.

From an operational standpoint, the decision to procure the F-35Bs are notable, as it comes hand in hand with a plan to use an existing ship design as an aircraft carrier. The presence of Japanese carriers armed with F-35Bs would be a clear signal of power projection to China, analysts have said, and also ease coordination with U.S. Marine Corps F-35Bs already stationed in Japan. Japan is in the process of standing up its first operational F-35 unit.

Japan’s plan calls for 45 F-35s, including 18 B models, to be acquired over the next five years.

Since coming to office, U.S. President Donald Trump has made increasing arms sale abroad a key effort, with Japan a frequent target.

In a company statement, prime contractor Lockheed Martin called the decision “a testament to the aircraft’s transformational capability and its increasing role in promoting regional stability and enhancing the US-Japan security alliance.”

Defense News' Asia Correspondent Mike Yeo in Melbourne, Australia, contributed to the this report.