South Korea’s presidential office said Friday that discussions with Washington on nuclear-powered submarines have proceeded on the clear premise that the vessels will be built domestically.

National Security Adviser Wi Sung-lac told reporters that “from start to finish,” both presidents discussed the program on the understanding that construction would take place in Korea. 

He said the option of building the submarines in the United States “was never raised.”

Wi added that President Lee Jae Myung explicitly told U.S. President Donald Trump during their summit that “we will build them here,” framing the issue as effectively settled.

Under a joint fact sheet released Friday, Washington approved Seoul’s plan to build nuclear-powered submarines and agreed to work closely on requirements, including securing enriched-uranium fuel.

Wi said the submarine hulls and reactors would be produced domestically, while the United States is expected to provide the nuclear fuel. 

He noted that cooperation with the U.S. industry could occur where needed, but the overall construction site “will be Korea.”

The fact sheet did not specify a build location, and Trump earlier mentioned a Philadelphia shipyard, but Seoul maintains the location lacks the facilities and that logistical and regulatory hurdles make domestic construction the only viable option.