North Korean leader Kim Jong Un has vowed that his country “will not set a limit” on the number of nuclear weapons it builds, as it pushes forward with what he said is an exponential increase in the number of bombs it possesses.

Kim used a speech Monday marking the 76th anniversary of North Korea’s founding to lay out the policy, which he said was a response to the “grave threat” posed by an expanding U.S.-led “nuclear-based military bloc” surrounding his country, the official Korean Central News Agency reported Tuesday.

“We are now perfectly carrying out the policy on building the nuclear armed forces on increasing the number of nuclear weapons by geometrical progression,” he said.