The Philippine ambassador to Washington has warned of the danger of a US-led nuclear war against China as tensions intensify over the disputed Second Thomas Shoal in the South China Sea.

Clashes between Chinese coast guard ships and Philippine vessels seeking to take supplies and materials to the Sierra Madre—a Philippine hulk grounded on the tiny reef and manned by Philippine troops—have escalated in recent months.

In an article published on Wednesday, Jose Manuel Romualdez told the Financial Times: “It’s the most dangerous time… weapons of mass destruction are very real. You have several countries, major powers that have large arsenals of nuclear power.” He warned: “If anything happens, the entire Asian region will be completely included.”

Asked how a dispute over a reef could spark a major conflict, Romualdez referred to the incident that provided the immediate trigger for World War I, the assassination of Archduke Franz Ferdinand of Austria in Sarajevo. “It’s an analogy, but it could happen that way,” he said.

President Ferdinand Marcos Jr has warned that the killing of a Filipino in clashes near the shoal would cross a “red line.”

Romualdez declared that China was testing US resolve with its actions around the reef. “I don’t think… China should just simply dismiss [the US-Philippines military alliance] as something that is not serious, because it is serious,” he said.

Speaking at the Council on Foreign Relations on Monday, US deputy secretary of state Kurt Campbell declared the crisis over the Second Thomas Shoal was caused by one of many Chinese provocations that could “spark conflicts that would devastate the global economy.”

The Biden administration has warned Beijing that the 1951 US-Philippine Mutual Defense Treaty applies to the Sierra Madre and its crew. Campbell did not specify the conditions under which the Philippines or US would invoke the treaty, but he said it was important to “draw very clear, public and private lines” about what could trigger a military conflict.

While Washington and its allies denounced Chinese “provocations,” US imperialism has been instrumental for more than a decade in transforming the South China Sea into a dangerous flashpoint for war with China.

For decades, the US paid scant attention to the longstanding territorial disputes over islets, reefs and other small features in the South China Sea, involving China, the Philippines, Vietnam, Malaysia and Brunei.

Manila grounded the Sierra Madre, a World War II landing craft, on the Second Thomas Shoal in 1999 in a bid to bolster its claim to the reef in response to China’s reclamation of Mischief Reef—another part of the disputed Spratly Island group.

In 2010, the Obama administration ratcheted up tensions over the South China Sea as it was preparing to announce its “pivot to Asia”—a diplomatic, economic and military strategy aimed at confronting and preparing for war against China.

Speaking at the Association of South East Asian Nations (ASEAN) security forum in July 2010, US Secretary of State Hilary Clinton declared that the US had a “national interest” in ensuring “freedom of navigation” in the South China Sea. In doing so, Clinton effectively declared Washington’s intention of challenging China’s territorial claims.

Chinese Foreign Minister Yang Jiechi responded by declaring that the US, by internationalising the disputes in South China Sea, was carrying out “virtually an attack on China.”

Since then, the US has deliberately exacerbated the situation by sending US warships and warplanes close to Chinese-controlled islets in the South China Sea on the pretext of asserting “freedom of navigation.”

Washington also provided crucial support for the Philippines to mount a case against China’s maritime claims in the Permanent Court of Arbitration in the Hague, based on the UN Convention of the Law of the Sea (UNCLOS). In 2016, the court found against China’s historic claims to most of the South China Sea as well as the existence of any territorial waters around tiny features such as the Second Thomas Shoal.

While the US and its allies routinely assert that the 2016 ruling against China vindicated Philippine claims, UNCLOS only applies to maritime issues and not to disputes concerning the ownership of land features. Moreover, Washington’s hypocritical demands that Beijing abide by international law ignore the fact that the US itself has not ratified UNCLOS.

The current confrontation around the Second Thomas Shoal takes place amid intensifying geo-political tensions fuelled by the US-NATO war against Russia in Ukraine, US backing for Israel’s genocidal war in the Middle East and the Biden administration’s escalating economic war against China.

Since Obama’s announcement of the “pivot to Asia” in 2011, the US has engaged in a comprehensive military build-up and restructuring throughout the Indo-Pacific and systematically strengthened its military alliances, basing arrangements and forged new military pacts throughout the region.

Romualdez’s warnings of nuclear war are not far-fetched and, if anything, are understated. The wars underway in Europe, in the Middle East and the reckless US-led confrontation with China are fronts in an unfolding global conflict involving nuclear-armed powers. Driven by the deepening global crisis of capitalism, US imperialism is engaged in a desperate attempt to shore up its global hegemony by all means, including military ones.

The Marcos regime in the Philippines is a willing stooge in the Biden administration’s reckless provocations against China in the South China Sea. Since coming to power, Marcos has extended the US military presence in the Philippines to include four new bases and greatly expanded joint military exercises with the US, including in the South China Sea.

Marcos has also overturned the understanding reached with China by his predecessor, President Rodrigo Duterte, who agreed to maintain the status quo in the South China Sea as he sought to boost Chinese trade and investment with the Philippines. In the case of the Second Thomas Shoal, that “gentleman’s agreement” signified that the Philippines would not reinforce or fortify the Sierra Madre.

China justified its blockade of the shoal by declaring that the Philippines was sending construction materials in breach of the agreement, which the Marcos administration has vehemently and repeatedly denied. It claimed that its vessels were only providing food and other essentials to the handful of Marines on the Sierra Madre.

In an interview last week, however, the Philippine ambassador Romualdez admitted that construction work had taken place. He claimed it was not “strengthening” the ship, but rather carrying out needed repairs. “We’re just doing a humanitarian act of giving these people a decent place to be in because they’re stationed there,” he said.

Contrary to Romualdez, the Financial Times noted that “people familiar with the situation said Manila had secretly reinforced the ship in ways that would extend its life.” Such moves, certain to inflame tensions with China, confirm in practice what Marcos declared last year, referring to Dutarte’s deal with China: “I am not aware of such agreement. If there was, I rescind it as of this moment.”

Romualdez has declared the disputes with Beijing in the South China Sea to be more dangerous than the situation in the Taiwan Strait, no doubt to bolster the case for greater US military aid to the Philippines. Since 2011, however, US imperialism has transformed the entire region into a tinder box, deliberately inflaming tensions with China not only over the South China Sea and Taiwan, but also the East China Sea, North Korea and India’s disputed borders with China.

Amid the current acute geo-political crises, any one of these volatile flashpoints has the potential to become the Sarejevo incident that precipitates a catastrophic war throughout Asia and internationally.