MELBOURNE, Australia — Japan has confirmed it will not use in-country final assembly facilities for its next lot of Lockheed Martin F-35 fighter jets.

A spokesperson from the U.S. ally’s Acquisition, Technology and Logistics Agency, or ATLA, told Defense News it will instead acquire aircraft imported from overseas for its upcoming fiscal 2019 contract.

The ATLA spokesperson referred Defense News to Japan’s Defense Ministry when asked why Japan will stop local assembly and checkout for its F-35s. The ministry has yet to respond to inquiries.

However, the recent defense guidelines and five-year defense plan released by the Japan government in late December said the country wants to “acquire high-performance equipment at the most affordable prices possible” and “review or discontinue projects of low cost-effectiveness.”

The Japanese government earlier that month approved the country’s defense budget, which includes $612.35 million for the acquisition of six F-35As for the upcoming Japanese fiscal year that runs from April 1, 2019, to March 31, 2020.

The budget additionally allocates $366.12 million for “other related expenses,” which include maintenance equipment tied to Japan’s F-35 program.

Japan has taken the local final assembly and checkout, or FACO, route since 2013 for the final assembly of F-35As it previously ordered. According to the ATLA spokesperson, the FACO facility, which is operated by Mitsubishi Heavy Industries, will continue to carry out production work until FY22 to fulfill the F-35As contracted by Japan between FY15 and FY18.

Japan has struggled to sustain its local industrial base, with recently released defense guidelines acknowledging it needs to overcome “challenges such as high costs due to low volume, high-mix production and lack of international competitiveness.”

According to Japanese budget documents, the country agreed to purchase 24 of the F-35As, with each aircraft costing an average $144.2 million, although the cost per aircraft has been on a downward trend, with the FY18 batch costing $119.7 million each. (Both figures are based on current exchange rates and do not take into account currency conversion fluctuations.)

In addition to the 42 F-35As, Japan has also indicated it intends to procure a further 105 F-35s, which will include 42 of the F-35B short-takeoff-and-vertical-landing variant. The defense plan has called for the acquisition of 45 F-35s over the next five years, of which 18 will be F-35Bs.