On June 21, 1989, the Swiss Federal Department of Foreign Affairs received a letter from the Permanent Observer of Palestine to the United Nations Office at Geneva informing the Swiss Federal Council "that the Executive Committee of the Palestine Liberation Organization, entrusted with the functions of the Government of the State of Palestine by decision of the Palestine National Council, decided, on 4 May 1989, to adhere to the Four Geneva Conventions of 12 August 1949 and the two Protocols additional thereto".
On September 13, 1989, the Swiss Federal Council informed the States that it was not in a position to decide whether the letter constituted an instrument of accession, "due to the uncertainty within the international community as to the existence or non-existence of a State of Palestine".