A new West Hollywood billboard courtesy of the AIDS Health Foundation is boldly linking online dating and hook-up apps (namely Grindr and Tinder) to STDs such as chlamydia and gonorrhea.

Related: Grindr Calls The 2016 Presidential Election

According to the Washington Post, the billboards have been installed in more than 50 spots around the city last week–including the one seen above, just a few blocks from Tinder's headquarters.

“These unprovoked and wholly unsubstantiated accusations are made to irreparably damage Tinder’s reputation in an attempt to encourage others to take an HIV test by your organization,” reads a cease and desist letter sent by Tinder attorney Jonathan Reichman to the AHF on Monday.

The AIDS Health Foundation is not backing down, calling apps likes these a “digital bathhouse for millennials, wherein the next sexual encounter can literally just be a few feet away–as well as the next STD.”

“While these sexual encounters are often intentionally brief or even anonymous," the statement continues, "sexually transmitted diseases can have lasting effects on an individual’s personal health and can certainly create epidemics in communities at large."

"We were surprised at the approach [the foundation] took, and paused the campaign in order to speak with them and assess our relationship," Grindr told the Los Angeles Times about cutting AHF ads from their app. “As one of the world’s largest gay platforms, we take this issue very seriously. At the end of the day, we are all on the same side in this issue, and strive to work with our partners and advocacy groups to achieve similar goals. A more connected and informed gay community is a better thing for us all.”