 On 21 February 2007, the United Nations Security Council authorised the African Union to deploy a peacekeeping mission with a mandate of six months.In March 2007, Ugandan military officials arrived on the ground in Somalia.On 20 August 2007, the United Nations Security Council extended the African Union's authorisation to continue deploying AMISOM for a further six months and requested the Secretary-General to explore the option of replacing AMISOM with a United Nations Peacekeeping Operation to Somalia.