A senior US official has presented what he describes as fresh evidence of an underground nuclear test that China allegedly carried out in June 2020.
Speaking at an event at the Hudson Institute think tank in Washington on Tuesday, Assistant Secretary of State Christopher Yeaw stated that a remote seismic station in Kazakhstan registered an “explosion” with a magnitude of 2.75.
He claimed the event originated 450 miles (720 km) away at China’s Lop Nor test site on 22 June, 2020.
“I’ve looked at additional data since then. There is very little possibility I would say that it is anything but an explosion, a singular explosion,” said Yeaw. He added that the data did not align with patterns typical of mining activities.
“It’s also entirely not consistent with an earthquake,” noted Yeaw, a former intelligence analyst and defence official with a doctorate in nuclear engineering. “It is … what you would expect with a nuclear explosive test.”
However, the Comprehensive Test Ban Treaty Organisation (CTBTO), the body responsible for monitoring nuclear test explosions, stated that the available data is insufficient to confirm Yeaw’s allegation with certainty.
A spokesperson for the Chinese embassy in Washington firmly rejected the claim. The official labelled the allegation about China conducting a nuclear test as “entirely unfounded” and described it as an attempt “to fabricate excuses for resuming” US nuclear testing.
“This is political manipulation aimed at pursuing nuclear hegemony and evading its own nuclear disarmament responsibilities,” Chinese embassy spokesperson Liu Pengyu said in an emailed statement.
“China urges the US to reaffirm the five nuclear-weapon states’ commitment on refraining from nuclear tests, uphold the global consensus against nuclear tests, and take concrete steps to safeguard the international nuclear disarmament and non-proliferation regime,” Liu added.
The allegation comes as US President Donald Trump pushes for China to join the US and Russia in negotiating a successor to the New START treaty, the last remaining strategic nuclear arms limitation agreement between Washington and Moscow, which expired on 5 February.
The lapse of the treaty has intensified concerns about a potential new nuclear arms race.
China denies nuclear testing allegation
China, which has signed but not ratified the 1996 Comprehensive Nuclear-Test-Ban Treaty, has consistently denied conducting an underground nuclear test since the allegation first surfaced at an international conference earlier this month. Beijing’s last officially acknowledged underground test was in 1996.
The PS23 seismic station in Kazakhstan is part of the CTBTO’s global monitoring network. The organisation’s Executive Secretary, Robert Floyd, confirmed in a statement that the station recorded “two very small seismic events” occurring 12 seconds apart on 22 June, 2020.
Floyd explained that the CTBTO’s system is designed to detect events consistent with nuclear test explosions with a yield of 551 tonnes (500 metric tonnes) of TNT or greater.
“These two events were far below that level. As a result, with this data alone, it is not possible to assess the cause of these events with confidence,” he stated.
Yeaw has suggested that China may have attempted to conceal the test through a technique called decoupling. This method involves detonating a device inside a large underground cavity to dampen the shockwaves travelling through the surrounding rock.
Like China, the US has signed but not ratified the test ban treaty, though both nations are obligated under international law to uphold its principles.
US conducted its last underground nuclear test in 1992 and now relies on a multibillion-dollar programme using advanced tools and supercomputers to certify its nuclear warhead stockpile.
Beijing has dismissed Trump’s call for trilateral arms control talks, arguing that its strategic nuclear arsenal is considerably smaller than those of the US and Russia.
Pentagon estimates that China currently operates over 600 warheads and is undergoing a significant expansion of its strategic forces, projecting the arsenal could exceed 1,000 warheads by 2030.
