The cyber attack on the Australian parliament’s computer networks earlier this month was carried out by a “sophisticated state actor” and also hit the major political parties, Prime Minister Scott Morrison said Monday.

The security breach in the parliament’s computer network, which is used by all lawmakers and their staff, was reported on February 8.

“I do not propose to go into the detail of these operational matters, but our cyber experts believe that a sophisticated state actor is responsible for this malicious activity,” Morrison told parliament.

Local media have quoted security sources as saying China could be behind the attacks, but Morrison did not specify.

The attempted hack forced parliamentarians and staff members to reset their computer passwords as a precaution. Ministers and their offices were not affected because they use different networks.

Morrison said during the course of a subsequent investigation it was revealed that the computer networks of the Liberal and National parties, who make up the coalition government, as well as the opposition Labor party, had also been affected.

Labor leader Bill Shorten said the attack was of “grave concern” and “we cannot be complacent.”

Morrison said there was “no evidence of any electoral interference.”

Australia is due to hold a federal election before May.