WASHINGTON (Reuters) - The U.S. State Department on Tuesday said Russia's decision to add jailed Kremlin critic Alexei Navalny and a handful of his allies to an official list of "terrorists and extremists" was disturbing, and it again called for Navalny's immediate and unconditional release.

       "This latest designation represents a new low in Russia's continuing crackdown on independent civil society," State Department spokesman Ned Price told reporters.

       (Reporting by Simon Lewis and Costas Pitas; Writing by Daphne Psaledakis)