A bipartisan group of U.S. lawmakers on Thursday asked Alphabet Inc’s Google (GOOGL.O) if it will re-enter the Chinese search engine market and if it would comply with China’s internet censorship policies upon its return.

Sixteen members of the U.S. House of Representatives, including liberal Democrats and conservative Republicans, said in a letter they had “serious concerns” about the potential step and asked Google if it would agree to restrict certain words, terms or events in China. The company did not immediately comment on Thursday.

Reuters reported last month Google planned to launch a version of its search engine in China that will block some websites and search terms, two sources said.

Representative David Cicilline, a Democrat and signer of the letter, wrote on Twitter that “Google should not be helping China crack down on free speech and political dissent.”

Other signers include Representative Michael McCaul, a Republican who chairs the House Homeland Security Committee.

The company could face questions about China when it testifies on privacy issues before a Senate panel on Sept. 26.

House Majority Leader Kevin McCarthy, a Republican, said on Tuesday that Google would be invited to testify on a number of issues. He wrote on Twitter that Google had worked with China and Russia on censorship but no longer wanted to do a technology deal with the U.S. Defense Department.