Taiwan wants to purchase radar aircraft from its security partner, the United States, to track its powerful neighbor China’s stealth fighter jets, local media reported on Tuesday.

The Taiwanese Defense Ministry told Newsweek that it had no additional comments on the matter. The U.S. State Department said it would not comment on or confirm potential or pending arms transfers before they are notified to Congress.

Why It Matters

Communist China has long claimed that the self-ruled Taiwan is part of its own territory despite never having governed the island. The Chinese military, which has one type of stealth combat aircraft in service, officially unveiled two new radar-evading jets last year.

While the U.S. does not have formal diplomatic ties with Taiwan, Washington is required by the Taiwan Relations Act, which is part of its One China policy, to provide the island with defensive arms. China has called the Taiwan-related U.S. law “illegal and invalid.”

What To Know

Citing a source with knowledge of the matter, Taiwan’s Central News Agency reported that Taipei has asked Washington for six E-2D Advanced Hawkeye airborne early warning aircraft to replace its older E-2K Hawkeyes.

The Hawkeye and the Advanced Hawkeye aircraft have a radar rotodome attached to their upper fuselage, providing airborne early warning and airborne battle management, as well as command and control functions, according to their main operator, the U.S. Navy.

Northrop Grumman, the manufacturer of the Advanced Hawkeye aircraft, says that it can track over 3,000 air and ground targets simultaneously. It is equipped with Lockheed Martin’s AN/APY-9 radar, which has a detection range of at least 300 nautical miles.

Stealth technology makes an aircraft less visible on radar but the AN/APY-9 radar has the ability to detect smaller targets at a greater range, making it a countermeasure to radar-evading aircraft such as the Chinese J-20, as well as the country’s newly announced J-20S and J-35A jets.

“China urges the U.S. to immediately stop arming Taiwan and stop the dangerous moves that undermine peace and stability in the Taiwan Strait,” China’s embassy in Washington, D.C., told Newsweek, warning that Beijing is justified in taking “resolute countermeasures.”

What People Are Saying

A U.S. State Department spokesperson told Newsweek: “Consistent with the Taiwan Relations Act, the United States will continue to enable Taiwan’s self-defense capabilities.”

Liu Pengyu, spokesperson for the Chinese Embassy in Washington, D.C., told Newsweek: “[U.S. arms sales to Taiwan] seriously undermine China’s sovereignty and security interests, harm China-U.S. relations and peace and stability across the Taiwan Strait, and send a gravely wrong message to ‘Taiwan independence’ separatist forces.”

U.S. defense contractor Northrop Grumman, manufacturer of the E-2D aircraft, said: “The E-2D gives the warfighter decision dominance through battlespace awareness, air and missile defense, and multiple sensor fusion capabilities in an airborne system.”

What Happens Next

It remains to be seen when the second Trump administration will approve its first arms sale to Taiwan. President Donald Trump suggested last summer that he would not defend Taiwan from China and the island should pay the U.S. for protection.