TAIPEI (Taiwan News) — Taiwan’s public bike sharing service YouBike has reportedly been hacked, exposing the information of 21,000 users to scammers.

Taipei’s transportation department was notified of the data breach by YouBike on May 17, per UDN. YouBike systems were attacked by an overseas connection that attempted to steal usernames, passwords, transaction information, and registered cellphone numbers, the company said.

YouBike said it had provided information to the relevant government authorities. Taipei's transport management head Liao Yuan-ling (廖苑伶) said all YouBike users should review their account information and transaction records for irregularities.

Liao warned the public to be wary of calls or text messages claiming to have recovered user data, as they may be fraudulent. She said users should confirm they are speaking with YouBike’s customer service when receiving communications, whose phone number for Taipei is 1999 (extension 5855), or 08-8978-8822.

Transport bureau staff have been sent to the Taipei and New Taipei offices of YouBike to conduct an investigation, and Liao said further staff will be sent next week.