The chairman of the US joint chiefs of staff has said that Taliban and al-Qaeda fighters are becoming "more sophisticated, more effective, and more dominant".
Speaking on a visit to Kabul, Admiral Mike Mullen said he was increasingly concerned about threats from fighters based across the border in Pakistan.
Meanwhile, America's second highest ranking general in Afghanistan has said the planned deployment of 30,000 more US troops will take longer than expected.
Al Jazeera's Todd Baer reports.
Source: Al Jazeera