MOSCOW -- Fourteen prisoners at a Russian hard-labor camp escaped to freedom by digging a long tunnel under the prison compound fence, police officials said Friday. Police in the Volga region where Novo Ulyanovsk prison is located, have been placed on alert to try to catch the prisoners, the officials said, as quoted by the Ria Novosti news agency after the discovery of the tunnel. It was the biggest single escape recorded in post-Soviet Russia, AFP reported. Russia has one of the highest incarceration rates in the world, with just under one million of its 145 million inhabitants imprisoned.