US Secretary of State Hillary Clinton and US special envoy to Pakistan and Afghanistan Richard Holbrooke called on President Asif Ali Zardari here Wednesday, report said. Clinton and Holbrooke visited the hotel where the President Zardari is staying and held an hour-long meeting with him on breakfast. The details of the meeting have not been released to the media. However, it was speculated that the agenda of the forthcoming meeting between US and Paksitani Presidents and recent political and security development in Pakistan and Afghanistan.