U.S. Congressional Armenian Caucus Co-Chairmen Frank Pallone and Joe Knollenberg congratulated Serzh Sargsyan on his appointment as RA Prime Minister. "Armenia has been and continues to be US's valuable ally and partner in the fight against terrorism. Congratulating You on the appointment, we express hope that Armenia and the United States will continue to cooperate in a number of issues important for both countries," the message of congressmen says, the RA Press Office reports.