Obama is focusing on US security in deciding whether to send up to 40,000 more troops to Afghanistan, as requested by his commanding general on the ground, Clinton said.

'This is not the prior days when people would come on your show and talk about how we were going to help the Afghans build a modern democracy and build a more functioning state and do all of these wonderful things,' Clinton said.

'That could happen, but our primary focus is on the security of the United States of America, how do we protect and defend against future attacks. We do not want to see Afghanistan return to being a safe haven and a staging platform for terrorism as it was before.'

In a dig at the previous Republican Bush administration, she added: 'We came to do a mission. Unfortunately, it was not achieved in the last eight years.'

'We've made it very clear,' Clinton said. 'We want to get the people who attacked us.'