SAN FRANCISCO (Reuters) – Tech companies including Facebook (FB.O), Google (GOOGL.O) and Microsoft (MSFT.O) on Thursday pledged to improve and standardise annual disclosures around online child exploitation, as they fight off moves to limit encryption.

The Technology Coalition, which coordinates industry action around child sexual abuse, also said its 18 member companies would establish a “multi-million” dollar research fund to study patterns of abuse and build technological tools to prevent them.

Multiple governments have seized on child exploitation as a major issue in their fight to ban encryption in consumer technologies, which they argue allows criminals to operate with impunity.

“We’d love to move beyond just the number of reports that may be out there, to really understanding what those reports mean,” said Antigone Davis, Facebook’s global head of safety.

The coalition, whose companies collectively earn hundreds of billions of dollars in revenue each year, declined to provide more details, including specifics about which metrics would be tracked.

Child welfare advocates say the number of known child sexual abuse images has soared from thousands to tens of millions in recent years, as predators have increasingly used social networks to groom victims and exchange explicit images.

The U.S.-led “Five Eyes” alliance last year threatened to weaken legal protections and called on Facebook to suspend plans to extend end-to-end encryption across its messaging services.

Facebook generated more than 90% of U.S. child sexual abuse reports online last year, according to the National Center for Missing and Exploited Children.

U.S. lawmakers introduced the “EARN IT Act,” in March which would require tech companies to follow best practices to “earn” legal immunity from content posted on their platforms.

U.K. Home Secretary Priti Patel, who joined the Five Eyes calls, welcomed the industry’s latest moves but urged companies to “work quickly and go further.”

“The sexual abuse of children online is sickening and we must all work collaboratively to eradicate this crime,” she said.