ISLAMABAD : Ambassadors of Switzerland and the United States of America presented credentials to President Asif Ali Zardari at an impressive ceremony at the Aiwan-e-Sadr here on Wednesday. The Ambassadors called on the President separately and presented their credentials and discussed bilateral relations.The President felicitated the newly appointed Ambassadors to Pakistan and hoped they would work for further strengthening ties between their respective countries and Pakistan.Earlier upon arrival, Ambassador designate of Switzerland Christoph Bubb and Ambassador designate of USA Cameron P. Munter were presented guard of honour by a smartly turned out contingent of Pakistan Army and national anthems of the two countries were played – App