By Jack Mendel Russian President Vladimir Putin has declared four Ukrainian regions part of Russia, amid renewed warnings the Kremlin may use a strategic nuclear weapon. In a ceremony at the Kremlin, the authoritarian leader announced that Donetsk, Luhansk, Kherson and Zaporizhzhia would be subsumed by Russia, following four ‘referendums’, which were widely declared as illegal and a sham. During a speech in Moscow, the Russian leader held a minute’s silence for ‘fallen soldiers’, with thousands of troops now thought to have died in the war against Ukraine. He told the assembled audience, of th…