(NewsNation) — Top U.S. officials raised concerns about China’s rapidly advancing capabilities in front of members of Congress on Tuesday, as recent moves by the Asian superpower threaten U.S. national security.

Two men were arrested Monday for allegedly establishing a secret police station in New York City meant to harass dissidents of the Chinese government.

In February, a Chinese spy balloon was shot down off the coast of South Carolina. Officials later announced that the balloon was part of a large surveillance program that China had been conducting for “several years.

Classified documents leaked last month also revealed the presence of four additional Chinese spy balloons over the U.S., which officials were aware of.

America’s heartland has also raised concerns about China, with a bipartisan push on in many states to limit China’s farmland ownership in the U.S.

Earlier this year, the City Council in Grand Forks, North Dakota, voted to stop the construction of a corn milling plant by a Chinese company near a U.S. Air Force base following town outcry. However, critics of such legislation argue it is un-American to limit private property ownership.

On Tuesday, top Pentagon officials warned that China is also rapidly developing its nuclear arsenal.

The U.S. Defense Department is now keeping a list of companies it believes support the “modernization” of the People’s Liberation Army.

This all comes as top defense officials say China is not being responsive to the U.S.