BRUSSELS, April 19 (Reuters) - Adult content companies Pornhub, Stripchat and XVideos will have to do risk assessment reports and take measures to address systemic risks linked to their services to comply with new EU online content rules, the European Commission said on Friday.

The three companies were designated as very large online platforms last December under the Digital Services Act (DSA) which requires them to do more to remove illegal and harmful content on their platforms.

Pornhub and Stripchat will have to comply with these DSA obligations, among the strictest, on April 21 and XVideos on April 23, the EU executive said.

"These specific obligations include submitting risk assessment reports to the Commission, putting in place mitigation measures to address systemic risks linked to the provision of their services," it said in a statement.

The companies will also have to meet additional transparency obligations, including related to ads, and providing access to data for researchers.

Companies risk fines as much as 6% of their global annual turnover for DSA breaches. (Reporting by Foo Yun Chee)