Apple has taken down an app that uses crowdsourcing to flag sightings of U.S. immigration agents, apparently after being pressured by U.S. authorities.

ICEBlock, a free iPhone-only app lets users anonymously report and monitor activity by Immigration and Customs Enforcement (ICE) officers, was no longer available on Apple’s App Store as of Friday.

“We just received a message from Apple’s App Review that #ICEBlock has been removed from the App Store due to “objectionable content’,” the developer said in a social media post. “The only thing we can imagine is this is due to pressure from the Trump Admin. We have responded and we’ll fight this!”

The developer said last month that it had more than 1 million users. Even though it has been removed from the app marketplace, those who have already downloaded the app should still be able to use it.

Apple said it removed apps like ICEBlock due to the potential for risks that were raised by law enforcement.

Officials said last month that a gunman who opened fire on an Immigration and Customs Enforcement facility in Dallas had searched for apps that tracked the presence of ICE agents.

“We created the App Store to be a safe and trusted place to discover apps,” the company said in a statement. “Based on information we’ve received from law enforcement about the safety risks associated with ICEBlock, we have removed it and similar apps from the App Store.”

Downloads of apps like ICEblock have surged as the Trump administration steps up immigration enforcement with surprise raids. The technology has come under fire from authorities after agents were targeted.

In a July interview on Fox News, U.S Attorney General Pam Bondi said crowdsourced apps that allow people to communicate about the location of law enforcement officers is not allowed, specifically referring to ICEBlock developer Joshua Aaron.

“We are looking at him and he better watch out because that’s not a protected speech,” Bondi said at the time.

ICEBlock and other crowdsourcing aps apps like are the ones being targeted, but crowdsourced technology has become common in the app store, and is still available through other apps.

Navigation apps like Waze or Google Maps for Android phones have been in use for years. Part of their draw is that users are alerted to police speed traps by other drivers. Users of those apps have suggested they can be used to post updates about “icy conditions.”

Waze and Google Maps have not been targeted by U.S. officials.