Russian authorities are not allowing four Israelis convicted in Russia to serve their sentences in their homeland until Israel extradites Leonid Nevzlin, the Israeli newspaper Yedioth Ahronoth reports. According to the publication, four Israelis are being held in one of the Moscow prisons - Eli Katz, Shimon Hirshhorn, Vladislav Kogan and Shalom Kasirer, convicted of smuggling uncut diamonds. The publication claims that Russia, which is demanding Israel to extradite businessman Leonid Nevzlin, is using imprisoned Israelis as hostages.