LG Uplus, the third-largest wireless carrier in South Korea, said that last month’s cyber security incident had affected 290,000 users.

On January 10, LG Uplus disclosed that personal data of 180,000 customers, including their names, birth dates and phone numbers, had been breached.

The company said on its website it found personal data of about 110,000 more customers, who had terminated their subscriptions, was also compromised.

LG Uplus had been storing the data under the e-commerce consumer protection law. The leaked data does not include financial information.

“We are cooperating with the investigation by the authorities and the government to determine when and how the personal data was leaked,” LG Uplus said.

The case is being investigated by the Seoul Metropolitan Police Agency, the Personal Information Protection Commission and the Korea Internet & Security Agency.

“We will strengthen our monitoring system so that such an incident does not happen again and do our best to come up with countermeasures,” said the agency.