The U.S. has warned Russia of “consequences” if opposition leader Alexei Navalny, now on a hunger strike for 18 days in a notorious Russian prison, dies. “We are looking at a variety of different costs that we would impose, and I’m not going to telegraph that publicly at this point, but we have communicated that there will be consequences if Mr. Navalny dies,” U.S. National Security Advisor Jake Sullivan told CNN in response to reports that Navalny could suffer cardiac arrest or kidney failure at any moment.

Meanwhile, Andrei Kelin, Russia’s ambassador to the UK, was on British Sunday morning television, promising that the Putin foe “would not be allowed to die in prison” and insisted that he was being “taken care of” and that recent reports about his failing health were only to “attract attention.” Navalny, 44, was nearly fatally poisoned in August 2020 by suspected Russian agents working on behalf of Putin. Navalny’s supporters have called for nationwide protests on April 21 demanding he be released.