Summary This content was produced in Russia, where the law restricts coverage of Russian military operations in Ukraine. MELEKHOVO, Russia, June 19 (Reuters) - Jailed opposition leader Alexei Navalny appeared before a Russian court on Monday to defend himself against new charges of extremism that could extend his prison term by decades. The hearing took place at the IK-6 penal colony in Melekhovo, about 235 km (145 miles) east of Moscow, where Navalny is already serving sentences totalling 11-1/2 years. His supporters accuse Moscow of trying to break him to silence his criticism of President Vladimir Putin, something the Kremlin...