Dozens of human rights groups signed on to an open letter today protesting Google’s plans for China, as CEO Sundar Pichai is scheduled to testify before a House committee tomorrow.

“We are writing to ask you to ensure that Google drops Project Dragonfly and any plans to launch a censored search app in China, and to re-affirm the company’s 2010 commitment that it won’t provide censored search services in the country,” the letter, which is addressed to Pichai, begins.

Dragonfly project “is likely to set a terrible precedent”

Google has faced intense scrutiny since it was revealed that the company planned to launch a search product that would comply with the Chinese government’s surveillance and censorship demands. The company has continued to claim that the project was only exploratory.

More than 60 NGOs signed the document, as well as individuals including Edward Snowden, saying they were “disappointed” by a previous letter from Google. By implementing the project, codenamed Dragonfly, the groups and individuals write, they “fear that the company may knowingly compromise its commitments to human rights and freedom of expression, in exchange for access to the Chinese search market.”

“Actively aiding China’s censorship and surveillance regime is likely to set a terrible precedent for human rights and press freedoms worldwide,” the letter continues.

The letter was only one source of pressure on Monday. A group of Tibetan rights groups and consumer advocates announced that they had received more than 50,000 signatures calling on Google to cancel its plans for China.

Google employees, meanwhile, have continued to pressure the company internally, with hundreds signing on to an open letter protesting the project. “It’s time for Google to uphold its own principles,” Jack Poulson, a former Google senior research scientist who resigned over Dragonfly, said during a media briefing.

Pichai is expected to face a bipartisan grilling in front of the House Judiciary Committee tomorrow, and while the scheduled topic is Google’s collection and filtering of data, Dragonfly will almost certainly be on the agenda for many lawmakers.