A new arms-control report expected to be made public by the State Department shows the United States is concerned that China is conducting secret nuclear tests despite a pledge against doing so, The Wall Street Journal reports.

There's reportedly no proof China is violating the Comprehensive Nuclear Test Ban Treaty, and the alleged tests are reportedly not very powerful, but Washington's suspicions are driven by "high tempo" activity at China's Lop Nur test site, extensive excavations at the site, and Beijing's "purported use of of special chambers to contain explosion," per the Journal.

Additionally, the U.S. noticed interruptions in data transmission of radioactive emissions and seismic tremors from Chinese monitoring stations — which are part of an international network of sites to verify treaty compliance — in recent years. The Trump administration's report claims the data was deliberately blocked by Beijing, but a spokesperson for the body that oversees the international test ban treaty said those interruptions came during a negotiating process between the CTBT organization and the Chinese government.

Either way, the report could certainly exacerbate tensions between Washington and Beijing, which are already rising because of longstanding trade disputes and, more recently, the U.S.'s criticism of China's handling of the COVID-19 coronavirus outbreak that originated in Wuhan. Read more at The Wall Street Journal. Tim O'Donnell