Lahore: Lt Gen David Goldfein, Commander US Air Force Central Command called on Air Chief Marshal Tahir Rafique Butt, Chief of the Air Staff, Pakistan Air Force, at Air Headquarters, Islamabad today. Both the dignitaries remained together for some time and discussed matters of professional interest. The regional security issues and other areas of further co-operation were also discussed during the meeting. The souvenirs were exchanged between the two dignitaries at the occasion.