WASHINGTON — Pound for pound, the deadliest arms of all time are not nuclear but biological. A single gallon of anthrax, if suitably distributed, could end human life on Earth.

Even so, the Trump administration has given scant attention to North Korea’s pursuit of living weapons — a threat that analysts describe as more immediate than its nuclear arms, which Pyongyang and Washington have been discussing for more than six months.

According to an analysis issued by the Middlebury Institute of International Studies at Monterey last month, North Korea is collaborating with foreign researchers to learn biotechnology skills and build machinery. As a result, the country’s capabilities are increasing rapidly.

“North Korea is far more likely to use biological weapons than nuclear ones,” said Andrew C. Weber, a Pentagon official in charge of nuclear, chemical and biological defense programs under President Obama. “The program is advanced, underestimated and highly lethal.”