Dating apps with location technology add a certain excitement to nightlife in many of the world's thrumming metropolises. But in some places, they could get you arrested.

The developers of gay dating app Grindr are facing criticism from users and an American security company, as fears mount that the smartphone app might have put thousands at risk worldwide in societies where homosexuality is frowned upon or a crime by law. Germany's largest daily Sueddeutsche Zeitung reported Thursday that Grindr had apparently been used by Egyptian authorities to track down homosexuals -- an allegation which could not be independently verified by The Washington Post. The German newspaper points to an article published on the Web site CairoScene as well as an interview conducted with an activist who operates a Twitter profile under the name 'GrindrMap' and has created a related Web site. Speaking to The Post, the user confirmed the authenticity of the interview and said: "It's a huge problem if Grindr runs such an infrastructure and doesn't act responsibly."

The report comes amid rising fears within Egypt's homosexual community. On Sept. 6, seven men were arrested -- allegedly for "inciting debauchery" -- after a video showed the men attending what appeared to be a same-sex marriage ceremony on a Nile riverboat, Human Rights Watch reported. The organization warned that homosexuals faced extreme dangers in Egypt and said four other men were sentenced to up to eight years in prison in April for homosexual conduct.

Given such draconian sentences, even the possibility of Egyptian police officers using Grindr to locate homosexuals has raised fears among the app's mobile users. According to American security company Synack, it was extremely easy to track down the locations of homosexuals using the app over the last months. Grindr allows men to interact with each other using location data. Hence, those interested in dating can view profiles of other users in their proximity. Grindr also displays the distances to those users, but does not show their exact location.

Under normal circumstances, users would need to interact directly before agreeing on a place to meet. However, if three users position themselves in different areas and agree on a common target it is possible to locate this one person, according to Synack. The company provided The Post with a map it created to show that one only needs basic geometrical knowledge to track down users in any area. The Sueddeutsche Zeitung report does not indicate whether this particular method was the one allegedly utilized by Egyptian authorities.

On Aug. 28, Grindr reacted to the criticism saying that users could easily defend themselves against such surveillance by turning off their distance setting. On Sept. 5, however, the company published another statement showing much more concern than previously and announced it had changed the settings for users logging in from Russia, Egypt, Saudi Arabia, Nigeria, Liberia, Sudan and Zimbabwe. These are all countries in which homosexuals can face prosecution and Grindr users could potentially be at risk.

"Any user who connects to Grindr in these countries will have their distance hidden automatically by default... There are many more countries already being protected by this location change, and we will continue to add more to this list," the statement read.

However, there are still reasons to be nervous. "On September 9, we were no longer receiving relative distances for users in Cairo, however, we did get notified that there were users nearby,"  Synack said in an e-mail to The Post, referring to Grindr's most recent security updates. "A sophisticated attacker could potentially ascertain the users' exact location because it is still being reported to Grindr, even though it is not being communicated to other Grindr users."