WeChat File photo:Xinhua

US President Donald Trump's ban on transactions using popular Chinese messaging app WeChat will cut ties to families and friends in China, millions of users in the United States fear, as they become the latest casualties in the standoff between the two nations.

WeChat, owned by Chinese internet giant Tencent Holdings Ltd, is popular among Chinese students, expats and some Americans who have personal or business relationships in China. 

"I came to the U.S. for free access to information. I feel I'm targeted by Trump," said Tingru Nan, a Chinese graduate student at the University of Delaware. "I'm living in constant fear now thinking I might get disconnected with friends and families."

The ban will cut off far more than the up to 6 million Chinese people who live in the United States. In the past three months, WeChat has had an average of 19 million daily active users in the United States, according to analytics firms Apptopia.

Expats, who are adept at working around firewalls in their home country, are preparing backup plans while in America.

Some WeChat users have started to share backup contacts for a limited number of apps that are still available in China, including Microsoft Corp's Skype and LinkedIn.

"When in China I need to use VPN to make Gmail and Instagram work. I've never imagined that I need to do similar things in the U.S.," said Tao Lei, a Philadelphia-based tech worker.

Allison Chan, a Chinese-American in Florida, uses a VPN every time she visits China to access U.S. sites like Facebook, Google and Twitter.

"After the 45-day period is up, I'll experiment with it and see if we can still use WeChat," said Allison Chan, a Chinese-American in Florida.

She said WeChat has been a major tool for her and her parents to communicate with her grandparents in China.

"I understood the argument about security, but for me, it was more about how I'm going to talk to my family," Chan said. "My parents are worried about my grandparents because their health has been declining and they want to get constant updates about them."

Some Chinese expats in America worry that this is only the latest salvo in a worsening U.S.-China relationship.

"My parents are more worried than me when they saw the news," said Yun Li, a User Experience (UX) designer in Boston who is from Guangdong, south China. "They also asked me to seriously consider moving back to China given the current political environment."