30 kilotons (as opposed to 45 kilotons announced by India). However, some non-Indian experts agree with India. Dr. Harold M. Agnew, former director of the Los Alamos National Laboratory, said that India's assertion of having detonated a staged thermonuclear bomb was believable. The British seismologist Roger Clarke argued that seismic magnitudes suggested a combined yield of up to 60 kilotonnes, consistent with the Indian announced total yield of 56 kilotonnes. Professor Jack Evernden, a US seismologist, has always maintained that for correct estimation of yields, one should "account properly for geological and seismological differences between test sites." His estimation of the yields of the Indian tests concur with those of India. Indian scientists have argued that some international estimations of the yields of India's nuclear tests are unscientific. India says that the yield of its tests were deliberately kept low to avoid civilian damage and that it can build staged thermonuclear weapons of various yields up to around 200 kilotons on the basis of those tests. Another cited reason for the low yields was that radioactivity released from yields significantly more than 45 kilotons might not have been contained fully. Even low-yield tests can have a bearing on thermonuclear capability, as they can provide information on the behavior of primaries without the full ignition of secondaries. North Korea North Korea claimed to have tested its miniaturised thermonuclear bomb on January 6, 2016. North Korea's first three nuclear tests (2006, 2009 and 2013) had a relatively low yield and do not appear to have been of a thermonuclear weapon design. In 2013, the South Korean Defense Ministry had speculated that North Korea might be trying to develop a "hydrogen bomb" and such a device might be North Korea's next weapons test. In January 2016, North Korea claimed to have successfully tested a hydrogen bomb, but only a magnitude 5.1 seismic event was detected at the time of the test, a similar magnitude to the 2013 test of a 6–9 kt atomic bomb. Those seismic recordings have scientists worldwide doubting North Korea's claim that a hydrogen bomb was tested and suggest it was a non-fusion nuclear test. On September 9, 2016, North Korea conducted their fifth nuclear test which yielded between 10 and 30 kilotons. On September 3, 2017, North Korea conducted a sixth nuclear test just a few hours after photographs of North Korean leader Kim Jong-un inspecting a device resembling