Key developments on April 3: Zelensky: Russia preparing to mobilize additional 300,000 troops by JuneUkraine, Finland sign long-term security agreementZelensky: Russia launched over 4,000 missiles, Shahed drones, guided aerial bombs on Ukraine in MarchMilitary intelligence: Russia has roughly 200 Su-34, Su-35 jets, 7 A-50 planesPolitico: Allies consider moving Ramstein group under NATO control to shield it from TrumpRussia is preparing to mobilize an additional 300,000 troops by June 1, President Volodymyr Zelensky said during a joint press conference in Kyiv with Finnish President Alexander S…