Drones - is their use breaching international law?

The use of military drones (Unmanned Aerial Vehicles or UAV) has been questioned by the United Nations Special Rapporteur on Extrajudicial Executions (Mr Philip Alston).  The issue is whether they are being used for such executions.  Mr Alston is concerned that they may be being used in a framework which breaches international humanitarian or human rights law.  He also claimed that strikes have killed civilian targets.  

Does the use of a drone really differ all that much from a squad of soldiers coming over the hill and shooting the enemy?  Is their use both legal and a legitimate military response?  Is there a legal difference between their use in Afghanistan as opposed to Pakistan?  See:

ABC News

                                                                            

Washington Independent

Afghanistan Conflict Monitor

and also see UN Involvement in Afghanistan which is authorised by UN Security Council Resolutions.

The International Security Assistance Force and the UN Assistance Mission in Afghanistan

An interesting website relating to Extrajudicial Executions is that of the Centre for Human Rights and Global Justice, New York University School of Law

An interesting item appears on Opinio Juris.  Alan Dershowitz defends Israeli assassinations in Dubai.  Something of a comparison is made with the use of drones.