Former U.S. National Intelligence Director Dennis Blair reportedly believes North Korea has eight to ten nuclear warheads.

Japan’s Nihon Keizai Shimbun says Blair, who headed the National Intelligence Service until May, made the claim in an interview on Friday.

Blair reportedly added that the North is presumed to have used the plutonium it extracted from its nuclear facilities at Yongbyon to produce its nuclear weapons.

According to the paper, Blair said that although it is unclear if the North has the capability to load nuclear warheads onto missiles, Pyongyang is likely to have the capacity to load the warheads on boats and have the boats enter U.S. ports. As a result, Blair said the U.S. is just as susceptible to the North’s nuclear threats as South Korea, China and Japan.