The new chief of US and Nato forces in Afghanistan has vowed to protect Afghan civilians when he takes up his post.Gen David Petraeus has been briefing allies and partners at Nato HQ in Brussels before heading to Kabul.The general said he had no plans to change current rules of engagement, which limit some uses of force to prevent civilian casualties.However, he said he would look into the application of the rules, which critics say put US troops in danger.The general was unanimously confirmed in the post by the US Senate on Wednesday.He replaces Gen Stanley McChrystal, who was removed after he and his aides mocked and criticised senior US officials in a magazine article.