The government has restated a target of removing UK troops from Afghanistan by 2014.
Leaked documents to a Sunday newspaper suggested a timetable for a phased transition to Afghan forces could begin within months.
But Defence Secretary Dr Liam Fox said 2014 remained the target for the handover of security control to Afghan forces.
Earlier, it was revealed that aid to the country is to be increased by 40%.
During and interview on the Andrew Marr Show, the defence secretary refused to comment on the Independent on Sunday's report on an accelerated timetable for troop withdrawals.
"It has always been our aim to be successful in the mission, and the mission has always said that the Afghan national security forces would be able to deal with their own security by 2014," he said.
BBC News
