Sensitive information of nearly 200 million people in the US was accidentally leaked by a marketing firm contracted by the Republican National Committee, the country's largest breach of electoral data to date, according to a media report.
The data leak by Deep Root Analytics contains personal information of roughly 61 per cent of the US population, technology news website Gizmodo reported.
The 1.1 terabytes of data seems to have been collected from a wide range of sources - from posts on controversial banned threads on a social network, to committees that raised funds for the Republican Party, the report said.
Apart from personal details, the data also contained citizens' suspected religious affiliations, ethnicities and political biases, such as where they stood on controversial topics like gun control, the right to abortion and stem cell research, the report said.
The information was stored in spreadsheets uploaded to a server owned by Deep Root Analytics. It had last been updated in January when President Donald Trump, a Republican, was inaugurated and had been online for an unknown period of time.
"We take full responsibility for this situation. Based on the information we have gathered thus far, we do not believe that our systems have been hacked," Deep Root Analytics' founder Alex Lundry by quoted by the report.
"Since this event has come to our attention, we have updated the access settings and put protocols in place to prevent further access," Lundry said.
Although it is known that political parties routinely gather data on voters, this is said to be the largest breach of electoral data in the US to date and privacy experts are concerned about the sheer scale of the data gathered.
There are fears that leaked data can easily be used for nefarious purposes, from identity fraud to harassment of people under protection orders, or to intimidate people who hold an opposing political view.