China is using messaging service WhatsApp to hack the phones of Indian users, the Army warned in a video posted on Twitter on Sunday.

“The Chinese use all kinds of platforms to penetrate your digital world,” the Indian Army claimed. “WhatsApp groups are a new way of hacking into your system. Chinese numbers starting with +86 barge into your groups and start extracting all the data.”

The Army urged users to save contacts by name, check all WhatsApp groups and to be wary of unknown numbers. “If you change your mobile number, inform the group administrator. If you change your SIM card, destroy it completely.”

The warning comes four months after India’s Intelligence Bureau issued an advisory asking troops to delete apps such as WeChat, Truecaller, Weibo, UC Browser and UC News from their phones.