Federal guidelines on masking in the case of a nuclear explosion were not changed this week, said a spokesperson for the Federal Emergency Management Agency on Tuesday. The guidelines, posted on the Ready.gov website, were shared widely on social media after Russian President Vladimir Putin on Sunday said he would raise his country’s nuclear deterrence level, sparking fears that a nuclear conflict could break out amid Moscow’s invasion of Ukraine. The guidelines include ways to prepare and what to do during a nuclear explosion, recommending COVID-19-related rules such as wearing face masks and social distancing. “Continue to practice social distancing by wearing a mask and by keeping a distance of at least six feet between yourself and people who not part of your household,” the government guidance said. “If you are experiencing a medical emergency, call 9-1-1 and let the operator know if you have, or think you might have, COVID-19,” it added. …