Anders Fogh Rasmussen: Nato troops 'key to Afghan security'
4 February 2014 Last updated at 00:23 GMT
Failure to ensure an international presence in Afghanistan beyond the 2014 withdrawal date for Nato troops could create a security crisis in the country, the Nato secretary-general has warned.
Afghan President Hamid Karzai has so far refused to sign a security agreement with the United States, permitting a small number of troops to stay beyond the deadline.
Speaking to BBC Newsnight, Anders Fogh Rasmussen said a lack of international forces would make it "difficult to generate financial resources to sustain the Afghan security forces" - meaning the country would be unable to pay salaries.
But, he told Mark Urban, he does not think Mr Karzai will sign the agreement, meaning negotiations will need to be held with the country's new president, after the election on 5 April.