Monday was an ordinary day, but some moves by Japan and the United States could not help but cause heightened alarm.

Fumio Kishida, Japan's prime minister, announced on Monday Japan's purchase of 400 US-made Tomahawk cruise missiles to acquire so-called counterstrike capability to attack the missile launch sites of "enemies".

This is the fifth batch of Tomahawk missiles purchased by Japan. Reportedly, they are the most advanced ones, with a maximum range of 2,414 kilometers and capability to fly at subsonic speeds and low altitudes, making them difficult to detect by radar.

The question is whether Japan's massive arms purchases, especially these medium- and long-range missiles, constitute a proliferation of advanced cruise missiles. Is Japan breaking its pacifist Constitution by buying offensive weapons in bulk with the intention of attacking other side's bases first? Countries in the region cannot but be vigilant toward Japan.

Also on Monday, a P-8A anti-submarine patrol aircraft of the US Navy sailed through the Taiwan Straits. The US Seventh Fleet said it demonstrated the US' commitment to a "free and open Indo-Pacific".

However, it is clear to all that what the US has done deliberately disrupts the regional situation, jeopardizes peace and stability across the Straits and is a deliberate provocation against China.

If a civilian balloon that is blown to the US can be hyped up to the extent we have seen by the US side, what if a Chinese military aircraft, at a sensitive moment, runs into the sensitive waters of the US and makes a similar flight for a "free and open" Atlantic or Pacific?

The moves of Japan and its patron on the same day may be coincidental. But neither is up to any good. China should carefully monitor the situation. Although it does not seek a war, it must prepare for war in advance in the face of the two countries' persistent provocations.

Japan and the US are the real security threat to the region, not China.