(Adds details of letter, background on other letters, quote from senator)
WASHINGTON, Oct 12 (Reuters) - Alphabet Inc's Google unit has told U.S. lawmakers it was considering "a variety of options" to offer additional services in China, but declined to detail plans for addressing Chinese censorship.
The company has come under criticism after reports it was considering re-entering China's search engine market and would comply with its internet censorship and surveillance policies.
In an Aug. 31 letter to six senators made public on Friday, Google Chief Executive Sundar Pichai said the company was "thoughtfully considering a variety of options for how to offer services in China in a way that is consistent with our mission."
The letter was reported earlier by The Intercept, a news website. Google declined to comment.
Reuters and other outlets had reported in August that Google planned to launch a version of its search engine in China that would block some websites and search terms. The move would mark its return to a market it abandoned eight years ago on censorship concerns.
Senator Mark Warner, the ranking Democrat on the Intelligence Committee, said on Friday he was "really disappointed with Google's response," through the letter, to questions from senators about the company's plans in China.
Google said it was "unclear" if it would move forward with a search engine in China, and that it was "not in a position to be able to answer detailed questions."
"Their response to the Senate failed to provide any information about Google's reported plans to consider launching a censored search engine in China," Warner said. "Any effort to get back into China could enable the Chinese government in repressing and manipulating their citizens."
In September, a bipartisan group of 16 U.S. House lawmakers asked Google to disclose precautions it would take to protect the safety of its users if Chinese regulators allow its search engine to operate.
The letter said Google was "committed to promoting access to information, freedom of expression, and user privacy, as well as to respecting the laws of jurisdictions in which we operate."
On Thursday, three other U.S. senators wrote Pichai to explain why it delayed disclosing vulnerabilities with its Google+ social network. (Reporting by David Shepardson; Additional reporting by Paresh Dave in San Francisco; Editing by Will Dunham and Richard Chang)