China has lost the international legal case over strategic reefs and atolls that it claims in the South China Sea, which would give it control over the disputed waters.
The judgment by International Court of Arbitration in The Hague is overwhelmingly in favour of claims by the Philippines and will increase global diplomatic pressure on Beijing to scale back military expansion in the sensitive area.
China however was unmoved, as it has repeatedly said it does not accept the jurisdiction of the international court and will not abide by its ruling.
By depriving certain outcrops – some of which are exposed only at low tide – of territorial-generating status, the ruling effectively punches holes in China's all-encompassing ''nine-dash'' demarcation line that stretches deep into the South China Sea. It declares large areas of the sea to be neutral international waters.
The findings by the Hague tribunal contain a series of criticisms of China's actions and claims. The court declared that ''although Chinese navigators and fishermen, as well as those of other states, had historically made use of the islands in the South China Sea, there was no evidence that China had historically exercised exclusive control over the waters or their resources.
''The tribunal concluded that there was no legal basis for China to claim historic rights to resources within the sea areas falling within the 'nine-dash line'.''
China reacted angrily to the verdict. Xinhua, the country's official news agency, hit out at what it described as an ''ill-founded'' ruling that was ''naturally null and void''.
China's defence ministry said its troops would ''unswervingly safeguard state sovereignty, security, maritime rights and interests,'' according to state broadcaster CCTV.
The ruling will make grim reading for Beijing. None of the fiercely disputed Spratly Islands, the UN body found, were ''capable of generating extended maritime zones … [and] having found that none of the features claimed by China was capable of generating an exclusive economic zone, the tribunal found that it could - without delimiting a boundary - declare that certain sea areas are within the exclusive economic zone of the Philippines, because those areas are not overlapped by any possible entitlement of China.''
The tribunal also found that ''China had violated the Philippines' sovereign rights in its exclusive economic zone by (a) interfering with Philippine fishing and petroleum exploration, (b) constructing artificial islands and (c) failing to prevent Chinese fishermen from fishing in the zone.
The tribunal also held that fishermen from the Philippines (like those from China) had traditional fishing rights at Scarborough Shoal and that China had interfered with these rights in restricting access. The tribunal further held that Chinese law enforcement vessels had unlawfully created a serious risk of collision when they physically obstructed Philippine vessels.
The Hague tribunal also condemned China's land reclamation projects and its construction of artificial islands at seven features in the Spratly Islands, concluding that it had caused ''severe harm to the coral reef environment and violated its obligation to preserve and protect fragile ecosystems and the habitat of depleted, threatened, or endangered species''.
China's land reclamation ''was incompatible with the obligations on a state during dispute resolution proceedings'', it added, since it involved causing ''irreparable harm to the marine environment'', building a ''large artificial island in the Philippines' exclusive economic zone'', and destroying ''evidence of the natural condition of features in the South China Sea that formed part of the parties' dispute''.
Beijing claims 90 per cent of the South China Sea, a maritime region believed to hold a wealth of untapped oil and gas reserves and through which roughly $4.5tn of ship-borne trade passes every year. Vietnam, Malaysia, Brunei and Taiwan also contest China's claims to islands and reef systems closer to their territory than Beijing's.
Sporadic violence between Chinese vessels and those of south-east Asia militaries have broken out in recent decades and the verdict, the first international legal decision on the issue, could have unpredictable consequences.
The court case at the permanent court of arbitration in The Hague, the UN-appointed tribunal that adjudicates in international disputes over maritime territory, has been running since 2013.
The judgment does not allocate any of the outcrops or islands to rival countries but instead indicates which maritime features are capable under international law of generating territorial rights over surrounding seas.
China has previously stated that it ''will neither accept nor participate in the arbitration unilaterally initiated by the Philippines''. The tribunal ruled, however, that China's refusal to participate did not deprive the court of jurisdiction and that the Philippines' decision to commence arbitration unilaterally was not an abuse of the convention's dispute settlement procedures.
Last year, US officials claimed the Chinese had built up an extra 800 hectares (2,000 acres) on their occupied outposts across the South China Sea over the previous 18 months.
Prof Philippe Sands QC, who represented the Philippines in the hearing, said, ''This is the most significant international legal case for almost the past 20 years since the Pinochet judgment.''
The main focus of activity has been on Mischief Reef, where satellite images reveal the island is growing bigger, and is surrounded by fleets of dredgers and tankers.
Speaking on the eve of the court's ruling, Bonnie Glaser, a senior Asia adviser at the Center for Strategic and International Studies, said she did not anticipate a major escalation from Beijing over its findings but admitted its reaction was hard to predict. ''[If] the Chinese really do perceive that the ruling is just poking a finger in their eye I think there is a good possibility they will lash out,'' she said.
''I believe we have all underestimated Xi Jinping,'' Glaser said of China's strongman president who has pursued an increasingly assertive foreign policy on issues such as the South China Sea. ''He just seems quite comfortable with a high level of friction with every country.''
China's foreign minister spoke to the US secretary of state, John Kerry, by telephone last week to warn Washington against moves that infringe on China's sovereignty, Chinese state media reported.
And Beijing conducted military drills in the South China Sea, deploying at least two guided missile destroyers, the Shenyang and Ningbo, and one missile frigate deployed.
China says it follows a historical precedent set by the ''nine-dash line'' that Beijing drew in 1947 following the surrender of Japan. The line has been included in subsequent maps issued under Communist rule.
But the Philippines strongly contests China's claims, specifically on nearby islands it says are part of the West Philippine Sea. Manila argued in seven hearings that China has exceeded its entitlement under the UN convention on the law of the sea. That gives China 12 miles of territorial waters around islands it controls, far less than claimed under the nine-dash line.
Beijing has the support of Russia and Saudi Arabia but has also garnered backing from dozens of smaller nations far from and not greatly affected by the hearing, including landlocked African countries Niger and Lesotho, as well as Palestine, Afghanistan and Togo. Vanuatu, a Pacific island nation of fewer than 300,000 citizens, also supports Beijing.
The Philippines has been backed by the US, UK, France, Japan and others.
The Philippine president, Rodrigo Duterte, is widely considered unpredictable and his moves in the next days and weeks will help determine what could happen next.