<p>Russian President Vladimir Putin called U.S. President Donald Trump Sunday to thank him for a CIA tip that helped thwart a series of bombings in St. Petersburg, the Kremlin said.</p>
<p>Putin expressed gratitude during the call for information provided by the CIA that allowed Russia's top domestic security agency to track down and arrest a group of suspects that was planning to bomb Kazan Cathedral and other crowded sites, the Kremlin said.</p>