North Korea marks the founding anniversary of its military on Tuesday, and South Korea and its allies are bracing for the possibility that it could conduct another nuclear test or launch an intercontinental ballistic missile for the first time.

North Korea often marks significant dates by displaying its military capability. It so far has carried out five nuclear tests.

Such a move could test the developing North Korea policies of U.S. President Donald Trump, who has reportedly settled on a strategy that emphasizes increased pressure on North Korea with the help of China, the North’s only major ally, instead of military options or trying to overthrow North Korea’s government.

Trump spoke by phone with both the Japanese and Chinese leaders Monday. Chinese state broadcaster CCTV quoted President Xi Jinping as tellingintend to militarily respond to a North Korean nuclear or missile test. South Korea’s Yonhap news agency reported Monday that South Korean naval ships will conduct a training exercise with the aircraft carrier, the USS Carl Vinson.

In a statement released late Friday, North Korea’s Foreign Ministry accused Trump of driving the region into an “extremely dangerous phase” with the dispatch of the aircraft carrier and said the North was ready to stand up against any threat posed by the United States.

With typical rhetorical flourish, the ministry said North Korea “will react to a total war with an all-out war, a nuclear war with nuclear strikes of its own style and surely win a victory in the death-defying struggle against the U.S. imperialists.”

Adding to the tensions, North Korea detained