US soldiers killed despite Obama Koran apology "We're not out of the woods yet," he told ABC News. The reason that [the letter] was important is the same reason that the commander on the ground, General Allen, apologised. And that is to save lives. And to make sure our troops who are there right now are not placed in further danger. Speaking shortly before a White House dinner to honour US troops returning from Iraq, Mr Obama said that the latest violence would not derail plans for Nato forces to withdraw by the end of 2014. That doesn't mean there aren't going to be tragic incidents, that doesn't mean there aren't going to be some bumps in the road. We've been there for over a decade now and that creates strains but the trajectory we have now is one that I feel confident we can carry out," he said. The latest killings in the southern province of Kandahar took place outside of a base manned jointly by US and Afghan forces. Both of the gunmen were killed in a firefight. The shooting took place as a small number of foreign advisers returned to work in the government ministries from which they had been withdrawn after an Afghan policeman killed two US senior officers on Saturday. The close-range killing inside the Interior Ministry in Kabul stunned Nato and led to fresh questions about the US strategy of embedding small numbers of advisers in Afghan government departments and military units. Anders Fogh Rasmussen, Nato's secretary general, said alliance forces were showing "great restraint" in face of increasingly frequents attacks by the Afghan troops.