Chinese state media said Thursday that a military history buff found a collection of confidential documents related to the country’s military in a pile of old papers he bought for under $1.

The collector reported the documents to security units after recognizing their sensitive nature.

The reports didn't say what the documents were or whether anyone had been arrested, other than to say two people involved in the second-hand book and magazine business involved were being questioned.

The purchaser, identified only as a retiree surnamed Zhang, is an avid fan of military history and soon realized that the items contained information stamped as confidential.

China’s opaque state security bodies and the Communist Party-controlled legal system often make it difficult to tell what is considered a state secret. Chinese and foreign consultancies operating within the country have been placed under investigation by state security bodies for possessing information about the economy that in other countries would be considered part of the public record.

China's military has grown massively in recent years, and it now boasts the world's largest navy, an air force with cutting-edge stealth fighters and a gigantic missile force that appears intended to back the country's claims to the self-governing island of Taiwan, the South China Sea and disputed islands controlled by Japan, and ultimately driving its major rival the U.S. out of the region.

In response, the U.S. has strengthened ties with allies such as Australia, the Philippines, Japan and South Korea, while boosting arms sales and military cooperation with Taiwan.

FILE - Military delegates chat before the closing session of the National People’s Congress at the Great Hall of the People in Beijing, Monday, March 11, 2024. Chinese state media said Thursday, June 13, 2024, that a military history buff found a collection of confidential documents related to the country’s military in a pile of old papers he bought for under $1. (AP Photo/Ng Han Guan, File)

A Chinese history buff finds military secrets in a pile of old papers he bought for under $1