Understanding Obama's Afghan plan

US Defence Secretary Robert Gates arrived in Kabul on Tuesday to deliver the message to Afghan and US troops that the United States "is in this thing to win." But how to win this war and when to withdraw are still questions. A week after US President Barack Obama's announcement of his new Afghan strategy, some new details are emerging.

Gates said he will assure Afghan President Hamid Karzai that the US is committed to the fight. He expects Kabul to get serious about accelerating the training of Afghan forces to prepare for the day when U.S. troops begin to pull out.

Gates' unannounced visit comes a week after U.S. President Barack Obama approved the deployment of 30 thousand extra troops and laid the groundwork for a gradual U.S. withdrawal starting in July 2011.

However, days after the new plan being announced, new details are emerging, including on the number of US troops and the timetable for withdrawal.