U.S. Senate Foreign Relations Committee Chairman Bob Menendez and ranking member Jim Risch said on Thursday they were "deeply concerned" by growing tension and instability in Tunisia.

"President (Kais) Saied must recommit to the democratic principles that underpin U.S.-Tunisia relations, and the military must observe its role in a constitutional democracy," were ththey said in an emailed joint statement.

Tunisia has been thrust into a political crisis by Saied's recent move to dismiss the prime minister and freeze parliament for 30 days, leading major parties to accuse him of a coup.

(Reporting by Tom Arnold Editing by Mark Heinrich) ((Tom.Arnold@thomsonreuters.com; +442075428510; Reuters Messaging: tom.arnold.thomsonreuters.com@reuters.net))