The USS Carl Vinson-led aircraft carrier strike group has been sent to waters in the Western Pacific near the Korean Peninsula, the U.S. Navy’s Pacific Command and media reports said Sunday ahead of the anniversary of the birth of North Korea’s founder.

Pacific Command chief Adm. Harry Harris directed the Carl Vinson strike group to sail north and report to the waters after departing Singapore on Saturday. Media reports quoted anonymous U.S. officials as saying the move was in response to recent North Korean provocations.

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. The group will operate in the Western Pacific rather than carrying out previously planned port visits to Australia, Pacific Command said.

Deployments to the Western Pacific are not unusual, and just last month the Carl Vinson was in South Korea for annual joint military exercises.

There has been growing speculation that Pyongyang will conduct an intercontinental ballistic missile test soon, 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.

Pyongyang has a history of using the April 15 anniversary of North Korean founder Kim Il Sung’s birth to show off its military might, including new weapons. The North may use a military parade on that date this year to display its latest arms, including an ICBM.

The news comes on the heels of the first meeting between U.S. President Donald Trump and Chinese leader Xi Jinping.

U.S. officials said the two sides agreed to increase cooperation on trying to get North Korea to abandon its nuclear weapons. But in the two days of meetings, which wrapped up Friday, the most powerful message for the Chinese leader may have been Trump’s decision to launch U.S. missile strikes at Syria.

Those strikes added weight to Trump’s recent threat to act unilaterally against North Korea’s weapons programs amid its ramped-up missile and nuclear tests.

In a statement carried by the North’s Korean Central News Agency on Saturday, the country’s Foreign Ministry lambasted the Syria strike as “absolutely unpardonable” and an “undisguised act of aggression against a sovereign state.”

“Some forces are loud-mouthed that the recent U.S. military attack on Syria is an action of warning us but we are not frightened by it,” a Foreign Ministry spokesman was quoted by KCNA as saying.

The spokesman said the North’s nuclear arsenal is “a treasured sword of justice” in the face of what he called U.S. aggression.

“The reality today goes to prove that any aggression should be countered with force only and we were entirely just when we have … bolstered our nuclear force,” the spokesman said.

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.