Google says it will not renew a controversial contract with the Defense Department, bowing to public and internal pressure over its contribution to Pentagon drone strikes.

Google Cloud CEO Diane Greene told employees Friday that Google would honor its commitment to the Pentagon’s Project Maven program through March 2019, but would not seek a new contract at that time, a source familiar with the matter told CNN.

Project Maven uses artificial intelligence to enhance drone strikes. Google has also worked to develop machine learning algorithms that would help the Pentagon enhance its surveillance efforts generally.

Google’s involvement with the Pentagon has divided staff and 4,000 employees signed a petition demanding “a clear policy stating that neither Google nor its contractors will ever build warfare technology.” About a dozen employees resigned in protest.

The news of Google’s plan to end its involvement was first reported by Gizmodo. Google has not commented on the matter and will not say whether it plans to cease working with the Pentagon altogether after March 2019.

The source said Google does plan to outline its views on the ethics of its artificial intelligence work at some point in the near future.

The debate over Project Maven comes as military and law enforcement grow increasingly reliant on tech companies to fuel their surveillance efforts. Amazon’s decision to share its facial recognition technology with local law enforcement agencies has raised red flags among civil rights groups.

These contracts represent big business opportunities. Gizmodo reports that Google’s initial contract with the Pentagon was worth at least $9 million, and possibly as much as $15 million. But they also present a public relations crisis and appear to go against Google’s portrayal of itself as an innovative company working in the service of social progress.