Apple has taken down an app that uses crowdsourcing to track and anonymously flag sightings of American immigration agents.

ICEBlock, a free iPhone-only app that lets users anonymously report and monitor activity by Immigration and Customs Enforcement 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 already have downloaded the app should still be able to use it.

Apple did not respond to a request for comment.

“We created the App Store to be a safe and trusted place to discover apps,” the company said in a statement to other media outlets. “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 such as 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.