On 12 September 1962, during President Diosdado Macapagal's administration, the Philippine government claimed the territory of North Borneo, and the full sovereignty, title and dominion over it were "ceded" by the heirs of Sultan of Sulu, Muhammad Esmail E. Kiram I, to the Philippines. The Philippines broke off diplomatic relations with Malaysia after the federation was formed with Sabah in 1963, but probably resumed relations unofficially through the Manila Accord, in which the Philippines made it clear that its position on the inclusion of North Borneo in the Federation of Malaysia was subject to the final outcome of the Philippine claim to North Borneo. The representatives of Indonesia and the Federation of Malaya seconded that the inclusion of North Borneo into the aforementioned Federation "would not prejudice either the claim or any right thereunder". It was revealed later in 1968 that President Ferdinand Marcos was training a team of militants on Corregidor known as Operation Merdeka for infiltration into Sabah. The plan failed as a result of the Jabidah massacre.