Pact will allow 10,000 American troops to remain in the country and raises hopes for improved US-Afghan relationsAfghanistan is poised to sign a long-delayed security deal to allow 10,000 US troops to stay in the country, signalling that the newly inaugurated president, Ashraf Ghani, intends to repair frayed ties with Washington.Hamid Karzai, who stepped down as president on Monday, refused to sign the deal in a disagreement that symbolised the breakdown of Afghan-US relations.