Chief of staff’s comments place further pressure on Cameron to commit to Nato’s 2% of GDP target beyond 2016The head of the US army has expressed serious reservations about the impact of cuts on the capacity of British forces, heaping further pressure on David Cameron to commit to maintaining spending.The chief of staff, General Raymond Odierno, said he was “very concerned” about the falling proportion of national wealth devoted to the military and warned it could result in British units being forced to operate within US ranks rather than alongside them.