Onboard, Feb 16 (ANI): Union Foreign Minister, Salman Khurshid backed Afghanistan President, Hamid Karzai’s ‘calculations’ on signing of long-term security deal with US that would authorize American troops to remain in war-torn country after 2014. The Foreign Minister was speaking to mediapersons onboard after attending the inauguration ceremony of the first National Agriculture University of Afghanistan. Khurshid’s visit comes amid a rift between Karzai and the US, jeopardising their proposed bilateral security agreement that is vital for the limited presence of American forces in Afghanistan after the drawdown this year.