North Korea has blasted the United States for rerouting an aircraft carrier strike group to waters off the Korean Peninsula amid surging tensions, saying it is “ready to react to any mode of war.”

The state-run Korean Central News Agency quoted a Foreign Ministry spokesman as saying Monday that the dispatch of the USS Carl Vinson-led carrier strike group showed that “the U.S. reckless moves for invading the DPRK have reached a serious phase of its scenario.”

DPRK is the acronym for the North’s formal name, the Democratic People’s Republic of Korea.

“If the U.S. dares opt for a military action, crying out for ‘preemptive attack’ and ‘removal of the headquarters,’ the DPRK is ready to react to any mode of war desired by the U.S.,” the spokesman said.

The U.S. Navy’s Pacific Command rerouted the carrier group, which departed Singapore on Saturday, from planned port calls in Australia amid Pyongyang’s recent spate of missile launches and apparent signs of a sixth nuclear test. The Carl Vinson strike group, led by the Nimitz-class aircraft carrier of the same name, includes two guided-missile destroyers and a guided-missile cruiser.

Citing military sources, South Korea’s Yonhap news agency said the strike group was due to arrive around April 15.

The decision to reroute the Vinson group also came just days after U.S. cruise missiles struck Syria. Those strikes were widely interpreted as an implicit message to Pyongyang that the White House is not ruling out unilateral military attacks on the Kim regime.

“The prevailing grave situation proves once again that the DPRK was entirely just when it increased in every way its military capabilities for self-defense and preemptive attack with a nuclear force as a pivot,” the Foreign Ministry spokesman said.

“We will take the toughest counteraction against the provocateurs in order to defend ourselves by powerful force of arms and keep to the road chosen by ourselves,” he said, adding that the North would “hold the U.S. wholly accountable for the catastrophic consequences to be entailed by its outrageous actions.”

The North regularly serves up such vitriol for the U.S. and South Korea, but observers say the present situation on the Korean Peninsula has hit a fever pitch unmatched in recent years.

Nick Bisley, a professor of international relations at La Trobe University in Australia, called the pronunciations “completely par for the course.”

“If anything, one might have expected even more florid prose from KCNA, given their predilection for ’50s style over-the-top Stalinist rhetoric,” Bisley said. “My sense is that they are confident that this is bluster from the U.S. and that there is an extremely low likelihood of a military response from Washington anytime soon.”

In an interview Sunday, U.S. National Security Adviser Lt. Gen. H.R. McMaster called the move to send the strike group “prudent” amid Pyongyang’s “pattern of provocative behavior.”

He also said he had supplied President Donald Trump with a “range of options” for dealing with Pyongyang.

“This is a rogue regime that is now a nuclear capable regime. … So, the president has asked to be prepared to give him a full range of options to remove that threat,” McMaster said.

The Trump administration has said that all options — including military action — are on the table.

South Korea’s Defense Ministry said Tuesday that the Trump administration would not take any substantive military action against the North without “close cooperation” with Seoul.

“(Such a military operation, if any,) will be conducted under the robust South Korea-U.S. combined defense posture based on their close cooperation,” Yonhap quoted ministry spokesman Moon Sang-gyun as saying.

While U.S. carrier deployments to the Western Pacific are not unusual, the Carl Vinson visited South Korea just last month for annual joint military exercises. The strike group was also due to arrive the same week Pyongyang marks the April 15 anniversary of North Korean founder Kim Il Sung’s birth. The regime is likely to use the event to flaunt its military might, possibly with its sixth nuclear test or a military parade showcasing an intercontinental ballistic missile. The North is also set to mark the army’s foundation day on April 25. Pyongyang has a long history of using such anniversaries to flex its military muscles.

There has been growing speculation that Pyongyang will conduct an intercontinental ballistic missile test soon — possibly this month — after leader Kim Jong Un used a New Year’s Day address to claim that the North was in the final stages of developing such a weapon.

Last week, the North test-fired a missile into the Sea of Japan that was believed to have traveled just “tens of kilometers,” the Japanese government said.

That launch was the latest in a spate of tests this year, including the near-simultaneous firing of four ballistic missiles into the Sea of Japan last month — a move the North said was a rehearsal for attacking U.S. bases in Japan. Those missiles, three of which fell into Japan’s exclusive economic zone, flew about 1,000 km. Abe characterized that test as “a new level of threat.”

Missile experts said the hypothetical target of that drill appeared to be U.S. Marine Corps Air Station Iwakuni in Yamaguchi Prefecture. Observers said the undisguised threat to U.S. bases in Japan was rare, even for Pyongyang, which routinely serves up colorful invectives.

Pyongyang has conducted more than 20 missile launches and two nuclear tests over the past year as it seeks to master the technology needed to mount a warhead on a long-range ballistic missile capable of striking the continental United States. It has also been making apparent preparations for its sixth atomic test, according to analyses of recent commercial satellite imagery.

Experts said the tit-for-tat coercive measures between the U.S. and the North could speed up any time frame for a nuclear test.

“That probably shortens the odds on another nuke test — if Kim Jong Un decides to continue escalating,” said Euan Graham, director of the International Security Program at the Lowy Institute in Sydney.