Chinese hackers have been stealing information from major international telecommunications companies in order to spy on high-profile people, according to a report Tuesday from Cybersecurity firm Cybereason.

The hacking campaign was called Operation Soft Cell and likely began in 2017. The hackers were able to steal valuable confidential information from the telecom companies, such as call records, location data and device information. 

"The threat actor mainly sought to collect CDR data (call logs, cell tower locations, etc.) belonging to specific individuals from various countries. This type of targeted cyber espionage is usually the work of nation state threat actors," the report said. 

The operation was likely backed by the Chinese government and was used to gather intel on high-profile individuals, such as government officials. The report said the attack likely came from a hacking threat group called menuPass, which is allegedly connected to the Chinese Ministry of State Security (MSS). 

Cybereason Chief Executive Lior Dev told the Associated Press that the hacking operations turned the telecommunications companies into a "global surveillance system."

Cyber espionage has become a major topic in regards to U.S.-China relations. Under President Trump the U.S. has put Chinese cell provider Huawei on a blacklist, due to suspicions that the Chinese government uses the company's products to spy on the U.S. 

The U.S. Department of Homeland Security has warned against the government using Chinese-made drones, saying that the drones can be used for surveillance by China.

Washington's relationship with Beijing has remained tense, as the two countries are engaged in a trade war. Earlier this year, the Trump administration imposed tariffs of 10% on $200 billion of Chinese-made goods. The tariffs have caused controversy because major U.S. retailers such as Walmart have said that they will have to raise prices, which could hurt the American consumer.