The United States has tested a ground-launched medium-range cruise missile — just weeks after Trump formally withdrew from the landmark Intermediate-Range Nuclear Forces Treaty. Such a test would have been banned under the INF. Russia today condemned the test and said the U.S. is increasing “the destabilizing potential” of the situation.

Meanwhile, an international arms control official said that four Russian nuclear-monitoring stations went silent following a mysterious blast almost two weeks ago off Russia’s northern coast. U.S. experts suspect it was caused during a test of a nuclear-powered cruise missile. Seven people, mostly nuclear scientists, are believed to have died in the explosion, which caused a radiation spike in the surrounding area — and possibly even as far as Scandinavia — and fueled concerns over a renewed nuclear arms race between the U.S. and Russia.