Facebook, Microsoft, Twitter and YouTube would cooperate on a plan to help limit the spread of terrorist content online.

Facebook, Microsoft, Twitter and YouTube have announced they’ll start sharing data to reduce the spread of “terrorist content” online, shortly after European officials warned that U.S. technology companies need to do better at curbing online hate speech.

In a joint statement, the companies said they will create a shared industry database of unique digital “fingerprints” identifying violent terrorist images and recruitment materials they have removed from their services. The shared data, called “hashes,” is aimed at improving the efficiency at which tech firms control the spread of such content.

“There is no place for content that promotes terrorism on our hosted consumer services,” the companies said in a joint blog post. “When alerted, we take swift action against this kind of content in accordance with our respective policies.” The move comes a year after the same companies banded together to identify and remove child pornography using a similar technique. The technique was developed by the UK’s Internet Watch Foundation. It extends beyond social networks; Google scans every Gmail user’s account for child porn.

The program, which is expected to begin in early 2017, aims to assuage government concerns — and derail proposed new federal legislation — over social media content that is seen as increasingly driving terrorist recruitment and radicalization, while also balancing free-speech issues.

Technical details were being worked out, but Microsoft Corp. pioneered similar technology to detect, report and remove child pornography through such a database in 2009. Unlike those images, which are plainly illegal under U.S. law, questions about whether an image or video promotes terrorism can be more subjective, depending on national laws and the rules of a particular company’s service.

“We really are going after the most obvious serious content that is shared online — that is, the kind of recruitment videos and beheading videos more likely to be against all our content policies,” said Sally Aldous, a Facebook Inc. spokeswoman.

Social networks have faced criticism this year for doing too little to prevent their platforms for being used to spread terrorist propaganda. Amid pressure from the European Union, the companies agreed this year to remove content within 24 hours if it qualifies as hate speech or propaganda. Meanwhile, Twitter faced a lawsuit in the United States alleging that its slowness in removing posts from ISIS constituted material support to the terrorist group. The lawsuit was dismissed in August.