WASHINGTON — A new low-yield nuclear warhead, created at the behest of the Trump administration, has officially entered production.

The first production unit of the W76-2 warhead is underway at the Pantax Plant in Texas, according to a statement from the National Nuclear Security Agency.

“NNSA is on track to complete the W76-2 Initial Operational Capability warhead quantity and deliver the units to the Navy by the end of Fiscal Year 2019,” an agency spokesman said. The spokesman noted only the IOC units will be delivered this year, but declined to say how many warheads make up that total.

The warhead design is a modification of the W76-1 warhead for the Navy’s Trident ballistic missile, which has allowed NNSA to quickly turn around the design since it was ordered in last year’s Nuclear Posture Review. The warhead is designed to be smaller than the weapon detonated at Hiroshima, Japan, during World War II.

The system is controversial, however, with nonproliferation advocates and many Democrats in Congress arguing that, by their nature, all nuclear weapons are strategic, not tactical. They note that even a low-yield nuclear weapon is incredibly powerful (an estimated 60,000-80,000 people were wiped out by the atomic bomb used at Hiroshima), and they worry having a low-yield and high-yield warhead launched on the same submarine-launched missile creates a situation where an adversary doesn’t know which system is being used and therefore reacts as if the larger warhead has been launched.