2011 a 'turbulent' year for US-Pakistan relations
US military officials say they may yet take disciplinary action over the Nato attack which killed 24 Pakistani soldiers.
The incident proved disastrous for US-Pakistan relations, in a year when mistrust between them reached an all-time high.
Incidents such as the US killing of Osama Bin Laden in Abbottabad led to senior officials on both sides speaking publicly about their differences.
The BBC's Aleem Maqbool looks back at a year when a key international relationship lurched from crisis to crisis.