Russian police arrested a woman holding a child’s severed head outside a Moscow subway station on Monday, officials said. The woman — later identified as a 39-year-old nurse — had the head in her hands and was threatening to activate a bomb, authorities said. She was screaming, “I am your death!” “I’m a terrorist!” and “Allahu Akbar!” at passersby, but no explosives were found on her, witnesses told police. “I was on my way to the metro station from home. She was standing near the metro entrance and caught my attention because she was screaming Allahu Akbar,” said journalist Polina...