1980 United Nations — Treaty Series • Nations Unies — Recueil des Traités 347 Article 62. FUNDAMENTAL CHANGE OF CIRCUMSTANCES 1. A fundamental change of circumstances which has occurred with regard to those existing at the time of the conclusion of a treaty, and which was not foreseen by the parties, may not be invoked as a ground for terminating or withdrawing from the treaty unless: (a) The existence of those circumstances constituted an essential basis of the con sent of the parties to be bound by the treaty; and (b) The effect of the change is radically to transform the extent of obligations still to be performed under the treaty. 2. A fundamental change of circumstances may not be invoked as a ground for terminating or withdrawing from a treaty: (a) If the treaty establishes a boundary; or (b) If the fundamental change is the result of a breach by the party invoking it either of an obligation under the treaty or of any other international obligation owed to any other party to the treaty. 3. If, under the foregoing paragraphs, a party may invoke a fundamental change of circumstances as a ground for terminating or withdrawing from a treaty it may also invoke the change as a ground for suspending the operation of the treaty. Article 63. SEVERANCE OF DIPLOMATIC OR CONSULAR RELATIONS The severance of diplomatic or consular relations between parties to a treaty does not affect the legal relations established between them by the treaty except in so far as the existence of diplomatic or consular relations is indispensable for the appli cation of the treaty. Article 64. EMERGENCE OF A NEW PEREMPTORY NORM OF GENERAL INTERNATIONAL LAW ("JUS COGENS") If a new peremptory norm of general international law emerges, any existing treaty which is in conflict with that norm becomes void and terminates. SECTION 4. Article 65. PROCEDURE PROCEDURE TO BE FOLLOWED WITH RESPECT TO INVALIDITY, TERMINATION, WITHDRAWAL FROM OR SUSPENSION OF THE OPERATION OF A TREATY 1. A party which, under the provisions of the present Convention, invokes either a defect in its consent to be bound by a treaty or a ground for impeaching the validity of a treaty, terminating it, withdrawing from it or suspending its operation, must notify the other parties of its claim. The notification shall indicate the measure proposed to be taken with respect to the treaty and the reasons therefor. 2. If, after the expiry of a period which, except in cases of special urgency, shall not be less than three months after the receipt of the notification, no party has raised any objection, the party making the notification may carry out in the manner provided in article 67 the measure which it has proposed. 3. If, however, objection has been raised by any other party, the parties shall seek a solution through the means indicated in Article 33 of the Charter of the United Nations. Vol. 1155,1-18232