After negotiations, the Netherlands signed the New York Agreement with Indonesia on 15 August 1962, relinquishing control of Western New Guinea to the United Nations.

Right-wing politicians wanted that the "Dutch flag remain planted in at least one portion of the former colony" and cited the presence of oil around Sorong.

Indonesia also increased its military pressure on Dutch New Guinea by buying weapons from the Soviet Union and the Eastern Bloc.

[10] On 19 December 1961, Sukarno decreed the establishment of the People's Triple Command or Tri Komando Rakyat (Trikora) in order to annex what Indonesia called West Irian by 1 January 1963.

In preparation for the planned invasion, the Mandala command began making land, air, and sea incursions into West Irian.

Having failed to secure anything from the United States (Dutch membership in NATO was the possible reason), General Nasution went to Moscow in December 1960 to negotiate what eventually turned out to be a US$2.5 billion arms package with the Soviet government.

The United States did not support the surrender of West Papua to Indonesia, since the Bureau of European Affairs considered it an act of trading one occupying power for another.

However, in April 1961, Robert Komer and McGeorge Bundy began to prepare plans for the United Nations to give the impression that surrender to Indonesia was legal.

Indonesia bought various kinds of military equipment, including 41 Mi-4 and nine Mi-6 helicopters, 30 MiG-15, 49 MiG-17, ten MiG-19 and 20 MiG-21 fighter jets, 12 Whiskey-class submarines, 12 Komar-class missile boats, and one ex-Soviet Navy Sverdlov-class cruiser which was renamed the KRI Irian.

Air bases and landing strips which were common along the borders of Maluku and West Irian, were relics of imperial Japanese presence.

Owing to the support of Soviet submarines and bombers, Indonesian military forces could confidently launch attacks on Dutch troops.

However, according to Khrushchev's memoirs, Indonesian Foreign Minister Soebandrio let the Soviet willingness to actively provide military support leak to Howard P. Jones, the US ambassador in Jakarta.

[18][19] Admiral Sudomo revealed in a newspaper article in 2005 that six Soviet submarines supported the amphibious operations while stationed Bitang, East Sulawesi, tasked to attack the Dutch fleet in Manokwari.

[20] Submarine commander Rudolf Ryzhikov recalled in a Russian article he received orders on 29 July from Admiral Sergey Gorshkov to patrol a combat zone west of New Guinea and sink any shipping after midnight on 5 August.

[24][25] In his memoirs, Khrushchev freely admitted that during the West New Guinea crisis Soviet personnel had been commanding Indonesian submarines and piloting Tu-16s.

The plan called first for the insertion of small bands of Indonesian troops by sea and by airdrop, who would then draw Dutch forces away from areas where the exploitation phase would stage full-scale amphibious landings and paratroop operations to seize key locations.

[7] On 15 January 1962, the infiltration phase of Operation Trikora began when four Indonesian Navy motor torpedo boats attempted to land a unit of 150 marines on the south coast of New Guinea near Vlakke Hoek.

The inserted Indonesian troops conducted guerrilla operations throughout Western New Guinea from April 1962 onwards, but they were largely militarily ineffective.

The Indonesian Air Force began to fly missions in the area from bases on surrounding islands, with Soviet-supplied Tupolev Tu-16 bombers armed with KS-1 Komet anti-ship missiles deployed in anticipation of an attack against the HNLMS Karel Doorman.

[7][8] By the summer of 1962, the Indonesian military had begun planning a large-scale amphibious and air assault against Biak, the Netherlands' main power base in West Irian.

[8][11] On 13 and 14 August 1962, air drops of Indonesian troops were staged from Sorong in the northwest to Merauke in the southeast as a diversion for an amphibious assault against the Dutch military base at Biak by a force of 7,000 Army (RPKAD) and Air Force (PASGAT) paratroopers, 4,500 marines and 13,000 army servicemen, from various military districts (KODAMs).

In 1962, the Dutch naval presence in New Guinea consisted of five anti-submarine destroyers, two frigates, three submarines, one survey vessel, one supply ship and two oil tankers.

As part of the planned defence, the Dutch had considered using Marid 6 NNG to disrupt the Indonesian military's communication systems.

They are able to return except 7 members on board the vessel "Ho Sing Sang" which was shot by Dutch forces and presumed lost between Etna Bay and Watu Belah Islands.

[27] On 18 March 1962 at 15.15 from this post, on Gebe island, PG 300 consisted of 2 platoons and Command Company 191261, under the leadership of Lt. Nana attempt an infiltration to Waigeo.

[27] On 20 April 1962, 2 platoons 191260 PG 300 under the command of Sergeant Major Boy Thomas travelled from Yu island to Tanjung Dalpele on Waigeo.

Since it was unwilling to be drawn into a protracted conflict on the other side of the world, the Dutch government signed the New York Agreement, which handed the colony to an interim United Nations administration.

While the Netherlands was a member of the North Atlantic Treaty Organization (NATO) and thus an ally of the US, the Kennedy administration was unwilling to antagonize Indonesia since it was trying to court President Sukarno away from the Soviet orbit.

As part of the New York Agreement, it was stipulated that a popular plebiscite, called the Act of Free Choice, would be held in 1969 to determine whether the West Papuans would choose to remain in Indonesia or seek self-determination.

[30] However, US efforts to win over Sukarno proved futile and Indonesia turned its attention to the former British colony of Malaysia, resulting in the Indonesian-Malaysian Confrontation.