The AIDS Healthcare Foundation has just put up a billboard blaming two mobile dating apps—Tinder and Grindr—for the increase in sexually transmitted diseases (STDs).

The billboard showed the silhouettes of four men and women and wrote "Tinder, Chlamydia; Grindr, Gonorrhea," according to the Catholic News Agency.

 The message in the billboard encouraged the dating apps' users to get tested for such diseases.

"Mobile dating apps are rapidly altering the sexual landscape by making casual sex as easily available as ordering a pizza," the foundation's senior director Whitney Engeran-Cordova said in a statement.

"In many ways, location-based mobile dating apps are becoming a digital bathhouse for millennials wherein the next sexual encounter can literally just be a few feet away – as well as the next STD," she added.

Tindr has become a popular dating app because of its speed and ease of use. Just by looking at a person's photo, first name and age, a person can either swipe left (to pass) or right (to like). If the same person swipes right at a certain user, then a match has been made.

Tindr also makes use of GPS tracking and enables users to see just how far away their potential matches might be. The AIDS Healthcare Foundation says that enabling casual hook-ups are making things worse for the rise of STDs.

The people behind Tindr protested the inclusion of their company's name in the billboard even as they sought a cease and desist order against it.

"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 organisation," Tinder attorney Jonathan Reichman said in a letter sent to the AIDS Healthcare Foundation, as obtained by the Los Angeles Times.

In a recent study conducted by the Colorado Department of Public Health and Environment, 47 percent of patients who suffer from STDs were found to have met their partners through location-based online or mobile dating services such as Grindr, SCRUFF, and Craigslist.

The same report also revealed a 56 percent increase in the number of early syphilis cases from Jan. 1 to July 31, 1915 compared to the same period in 2014.