The Tlatelo1co Treaty contains a number of ambiguities. The most important and notorious of these concerns PNEs - nuclear explosions carried out for peaceful purposes (Article 18). The Treaty permits Parties to conduct such explosions and delineates procedures to be followed. However any peaceful nuclear explosion must be in accordance with Article I, which prohibits the testing and use of nuclear weapons and Article 5 which defines a nuclear weapon as 'any device which is capable of releasing nuclear energy in an uncontrolled manner and which has a group of characteristics that are appropriate for use for warlike purposes'.