Real-sounding but made-up news articles have become much easier to produce thanks to a handful of new tools powered by artificial intelligence—raising concerns about potential misuse of the technology.

What deepfakes did for video—producing clips of famous people appearing to say and do things they never said or did—these tools could do for news, tricking people into thinking the earth is flat, global warming is a hoax or a political candidate committed a crime when he or she didn’t. While false articles are nothing new, these...