WASHINGTON — U.S. researchers say North Korea could increase its nuclear arsenal from at least 10 weapons today to between 20 and 100 weapons in five years.

That is based on projections made by American expert

ina. The U.S.-Korea Institute at Johns Hopkins School of Advanced International Studies presented the findings Tuesday.

It comes as the U.S. and South Korea prepare for annual military drills that have angered North Korea, and as U.S. lawmakers push legislation that would tighten sanctions intended to restrict leader Kim Jong Un's access to the international banking system.

Secretary of State John Kerry said Tuesday the U.S. will keep working with allies to pressure Pyongyang to denuclearize.