A day before North Korea marks a major holiday, the US Trump administration sought to increase pressure on Pyongyang, holding presidential phone calls with China and Japan before a supercarrier heads toward the peninsula.

In just 11 days, Trump had another phone conversation with Chinese President Xi Jinping on Monday to discuss the security situation surrounding the Koreas. The US leader also spoke to Japanese Prime Minister Shinzo Abe.

The calls came amid speculation North Korea may be preparing a nuclear test in celebration of Tuesday’s anniversary of the founding of the Korean People’s Army.

The US’ Carl Vinson strike group, which is currently staging a joint naval exercise with Japanese destroyers, is due to arrive in waters off the peninsula within days in a fresh display of force.

Pyongyang’s propaganda machines Monday threatened to “bury (the aircraft carrier) at sea,” saying the nuclear-powered ship’s redirection demonstrates a looming invasion of the country.

“The world would clearly see how the US’ rash, arrogant aircraft carriers turn into a lump of scrap metal and gets buried at sea, and how the country vanishes from the Earth,” state-run website Uriminzokkiri said.

“Our super-hard-line responses include sudden, pre-emptive strikes involving land, naval, underwater and airmobile assets.”

Radio Pyongyang also said, “If the US starts a reckless provocation, we will respond to all-out war with all-out war, and to a nuclear war with our own nuclear strikes.”

With snowballing tension, Xi urged “restraint” during the call with Trump, once again emphasizing China’s opposition to any violations of UN Security Council resolutions.

“(China) hopes that the relevant parties can maintain restraint and avoid actions that would increase tensions in the Korean Peninsula,” Xi said, according to a statement from Beijing’s Foreign Ministry.

“The only way to realize a denuclearization in the Korean Peninsula and quickly resolve North Korea’s nuclear problem is for each relevant party to fulfill its duties

Ministry spokesperson Geng Shuang reiterated Xi’s remarks later in the day, saying the peninsula is in a “complex, sensitive and very tense situation” and urging no further actions to escalate it.

Abe said he and Trump agreed to continue to demand the North refrain from provocations, vowing to maintain tight vigilance in light of the ongoing naval drills.

In an interview with the Associated Press, Trump expressed confidence in his tactics of using economic and trade issues to encourage China to play a bigger role in changing North Korea’s course. Having managed to build a “really great relationship” with Xi through their first summit early this month, he would now show “flexibility,” he said.

“More importantly than him not being a currency manipulator, the bigger picture, bigger than even currency manipulation, if he’s helping us with North Korea, with nuclear and all of the things that go along with it, who would call ... ‘And also, you’re a currency manipulator.’ It doesn’t work that way,” Trump said. “Now maybe that’ll work out or maybe it won’t. Can you imagine?”

Pentagon spokesman Gary Ross also called on Pyongyang to “refrain from provocative, destabilizing actions and rhetoric,” while a State Department spokesperson told CNN the North must cease “all its illegal activities and aggressive behavior.”

“Provocations from North Korea have grown far too common and far too dangerous to ignore,” the spokesperson said. “We do not seek military conflict, nor do we seek to threaten North Korea. However, we will respond to threats to us or our allies accordingly.”

Seoul stepped up its warnings against any additional nuclear test or other provocations, though it said no special movements have been detected from across the border.

Defense Ministry spokesperson Moon Sang-gyun said Monday the allies are in “full readiness posture” for an underground detonation and currently discussing a joint exercise between the Carl Vinson strike group and the South Korean Navy.

Unification Ministry spokesperson Lee Duk-haeng acknowledged Beijing’s efforts to denuclearize the recalcitrant state, referring to a recent editorial in the Global Times that said China would not intervene even if the US strikes North Korea’s nuclear facilities.

“While it is not an official statement from the Chinese government, we understand that it is putting maximum pressure to resolve the situation, based on the view that the North’s nuclear and missile provocations pose a substantial threat to peace and stability on the peninsula and in Northeast Asia,” he said at a news briefing.

By Shin Hyon-hee (heeshin@heraldcorp.com) and Yeo Jun-suk (jasonyeo@heraldcorp.com)