Donald Trump’s nominee for chairman of the U.S. Joint Chiefs of Staff (JCS) expressed opposition to any potential reductions in U.S. military forces stationed in South Korea and Japan, citing North Korea’s increasingly sophisticated nuclear and missile capabilities as key factors in maintaining the current U.S. presence in the region.

“North Korea’s long-range missile and nuclear programs pose an immediate security challenge,” Dan Caine said in a written response to the Senate Armed Services Committee’s advanced policy question on the potential impact of reducing U.S. troop levels in South Korea or Japan.

Caine, a retired three-star general, previously served