The Intercept reported Friday that Google built a prototype for a censored search engine that would have allowed the Chinese government to more easily monitor users' queries by linking their searches with their phone numbers, citing sources familiar with the project, code-named "Dragonfly".
Google's reported plan to launch a censored version of its search engine in China has come under heavy criticism from a former Asia-Pacific head of the company's free expression issues who called it a "stupid move".
One of the most prominent names to leave the company is the research scientist Jack Poulson, who has worked with Google for a period of two years and five months.
Google is under mounting pressure to explain its intention to return to the Chinese market, which may see it comply with Chinese government censorship and surveillance requests.
In a statement to Fox News at the time of the letter, Google said it has "been investing for many years to help Chinese users, from developing Android, through mobile apps such as Google Translate and Files Go and our developer tools".More news: Alli, Lloris out for game against Liverpool
In addition to Mr. Cicilline, Thursday's letter was signed by Rep. Michael McCaul, Texas Republican and chair of the House Homeland Security Committee, as well as three other House Republicans and 11 Democrats.
He was among a handful who resigned, he told the Intercept online publication, which first reported on his action.
Poulson's resignation letter said: "Due to my conviction that dissent is fundamental to functioning democracies, I am forced to resign in order to avoid contributing to, or profiting from, the erosion of protection for dissidents".
Why it's important: Last month's announcement that Google might re-launch a censored version of its search engine in China has made waves around the Western tech world.
The congressmen then asked Pichai to answer 5 questions, including, "Is Google taking steps to ensure that individual Chinese citizens, or foreigners living in China, including Americans, will not be surveilled or targeted through Google applications or products?"More news: Google execs bemoan Trump election in 2016
House Majority Leader Kevin McCarthy, a Republican, said on Tuesday that Google would be invited to testify on a number of issues.
However, Pichai has said he wants Google to be in China serving its internet users.
Google's re-entry is not guaranteed as China has stepped up scrutiny of business dealings involving U.S. tech firms including Facebook Inc and Apple Inc amid intensifying trade tensions between Beijing and Washington.
Google's main search platform has been blocked in China since 2010, but it has been attempting to make new inroads into China.More news: Florence pours on the rain in the Carolinas, swelling rivers