The articles published today and over coming weeks are drawn from US state department cables which were sent earlier this year to WikiLeaks, an organisation devoted to exposing secrets of all kinds. The Guardian is one of five publications around the world which has had prior access to the material – around 250,000 cables in all – on condition that we observed common deadlines over the timings of release. The others are the New York Times, Le Monde, El País and Der Spiegel.

The leaked material is the third such exercise in which the Guardian and other publications have been involved. The previous two involved military records from the wars in Afghanistan and Iraq. The current release is of leaked dispatches from more than 250 US embassies and consulates worldwide. The documents range from unclassified to "secret". The latter is two rungs below the most confidential ranking of information: more than three million US citizens are cleared to see "secret" material.

WikiLeaks has not revealed the source of its information. It has played no part in the preparation, editing and reporting of the individual papers. Co-operation with WikiLeaks has been restricted to agreeing the dates on which we could cover specific regions. The news organisations have redacted some of the cables in order to protect a number of named sources and so as not to disclose certain details of current special operations. We have shared our redactions with WikiLeaks.

During the course of working on the material over many weeks each publication has formed its own individual judgments about specific stories. There are some cables the Guardian will not be releasing or reporting owing to the nature of sourcing or subject matter. Our domestic libel laws impose a special burden on British publishers.

All the publications involved have given early warning to the US government of our intention to publish. Government officials, who are aware of the general subjects we intend to cover, have not disputed the authenticity of the overall material. They have flagged up some specific, and some general, concerns.

The US state department has said that it has prepared for the release by reviewing thousands of cables and alerting relevant parties around the world in advance.