Chinese police are using a new anti-fraud app installed on more than 200m mobile phones to identify and question people who have viewed overseas financial news sites, according to individuals summoned by the authorities.

The app was launched in March by the public security ministry’s National Anti-Fraud Centre and blocks suspicious phone calls and reports malware. Police said it was needed to combat a surge in fraud, often perpetrated by overseas operations managed by Chinese and Taiwan nationals.

The ministry recommended that the app was downloaded but numerous local government agencies made it mandatory for their employees and individuals with whom they work, such as students and tenants.

One Shanghai-based user told the Financial Times he was contacted by police after accessing a US financial news service. He was also asked whether he had contacts abroad and regularly visited overseas websites.

The user, who asked not to be identified, said police seemed genuinely concerned about foreign scams. “But the questions they raised about whether I have contacted foreigners made me feel like they don’t want me accessing foreign websites,” he added. “I deleted the app after the meeting.”

A second user in eastern Shandong province said police called him on four consecutive days after the app showed he had visited what it labelled “highly dangerous” overseas information providers, including Bloomberg.

“They said they would remove the ‘dangerous’ label on Bloomberg but nothing happened,” the user said. “The authorities also don’t disclose how they determine whether an overseas website is fraud-related.”

The app has also generated thousands of privacy-related complaints online from people who said they had to download it in order to rent apartments or enrol their children in schools.

A dozen individuals told the FT they were uncomfortable giving the app 29 permissions, including live-monitoring of call logs, text messages and conversations, in order to install it on their phones.

“I am not going to give the authorities access to every aspect of my life in order to fend off scams,” said a Shanghai-based marketing manager who has ignored multiple requests to install the app.

Parents from across the country said they had to download the app before they were allowed to enrol their children in school. In Shenzhen, some tenants have been required to install it before signing rental leases.

“I have never seen such an abuse of government power to promote an unpopular app,” said an office worker in eastern Anhui province who had to download the app before he could apply for an identification card.

“This is a surveillance app that keeps track of everything on your phone,” added an office worker who deleted the app several hours after local authorities told him to install it. “I don’t need it, no matter how good its intentions are.”

According to official data, China arrested 361,000 people for wire or online fraud last year, compared with 73,000 arrests in 2018. In April, Li Bei, a spokesperson for the public security ministry, called such frauds the country’s “fastest-growing criminal activity”.

The app offers dozens of courses on fraud prevention. “It has played a significant role in fighting scams,” said Jiang Guoli, a senior public security official, at a press conference in June. Jiang added that the app had issued 23m alert messages within the first three months of its launch.

The ministry of public security and the National Anti-Fraud Centre did not respond to a request for comment.

Karman Lucero, a fellow at Yale Law School, said the app could be misused by the government. “It could certainly be used to develop valuable intelligence about who you are and what you do even without listening to your phone calls or reading the exact content of your text messages,” he said.

Additional reporting by Nian Liu