Six US senators have written to Google CEO Sundar Pichai asking about the tech giant's reported plan to create a censored Chinese version of its search engine. "What has changed since 2010 to make Google comfortable cooperating with the rigorous censorship regime in China?" asked the senators, including Florida Republican Marco Rubio, Fortune reported on Sunday.

According to the letter, Google's project is "deeply troubling and risks making Google complicit in human rights abuses" in China. Google in 2010 "refused to comply with Chinese government censorship requirements on ethical grounds, and essentially abandoned the market," said the report.