Beijing has unleashed a final salvo of defiance, propaganda and bravado with hours to go until a landmark court ruling that could deal a major blow to its territorial claims in the South China Sea.

More than three years after the Philippines asked the permanent court of arbitration in The Hague to dismiss many of China’s sweeping claims in the resource-rich region, the court is set to announce its decision at around 11am Tuesday CEST (10am BST).

China has refused to recognise the five-judge court’s authority and on Tuesday morning the country’s Communist party-controlled press lashed out at what it claimed was a United States-sponsored conspiracy to stifle its rise.

“China in the past was weak … but now it has multiple means at its disposal,” warned the Global Times, a nationalist Communist party tabloid, in an editorial, adding: “Provocateurs are doomed to fail.”

The China Daily, Beijing’s English-language mouthpiece, dismissed the court case as a “farce directed by Washington”.

“[The ruling] will not change the fact that China holds historical claims and sovereignty over those islands and reefs in the South China Sea, nor will it shake its resolve to defend every inch of them,” it said.

The newspaper argued that the damning findings of the Chilcot inquiry into the Iraq war showed Washington would be on “shaky ground” were it to engage in “a new round of US mudslinging against China”.

Xinhua, China’s official news agency, wrapped up an unremitting propaganda blitzkrieg by quoting Peruvian and Pakistani diplomats and an MP from Britain’s Labour party it claimed were supportive of Beijing’s position.

“Western media have hyped up the South China Sea issue for a long time, with reports full of prejudice and distortion. They have purposely created rumours, smeared China and deliberately overlooked voices of justice,” Xinhua claimed.

The permanent court of arbitration is set to rule on whether a series of Chinese-controlled rocks and reefs in the South China Sea should be considered islands which would therefore allow Beijing to claim the surrounding waters through exclusive economic zones.

The Philippines has also asked the court to consider whether international law supports China’s so-called “nine-dash line”, through which Beijing claims about 90% of the South China Sea.

Bonnie Glaser, the director of the China Power Project at the Center for Strategic and International Studies (CSIS) thinktank, said a ruling questioning or rejecting the “nine-dash line” would “really limit the amount of water that the Chinese could have any legal sovereignty claim to”.

“My sense is that their biggest fear is that there is an explicit finding that the ‘nine-dash line’ is contrary to international law,” she said. “That is something that they just cannot not abide, that they could not accept. And that would be very difficult for them to manage going forward.”