KUALA LUMPUR, Malaysia — In highway billboards and radio announcements, the government of Malaysia is warning of a new enemy: “fake news.”

On Monday, the lower house of Parliament passed a bill outlawing fake news, the first measure of its kind in the world. The proposal, which allows for up to six years in prison for publishing or circulating misleading information, is expected to pass the Senate this week and to come into effect soon after.

The legislation would punish not only those who are behind fake news but also anyone who maliciously spreads such material. Online service providers would be responsible for third-party content, and anyone could lodge a complaint. As long as Malaysia or Malaysians are affected, fake news generated outside the country is also subject to prosecution.

What qualifies as fake news, however, is ill defined. Ultimately, the government would be given broad latitude to decide what constitutes fact in Malaysia.