Sens. Dick Durbin (D-Ill.) and Tom Coburn (R-Okla.) demanded answers from Twitter CEO Dick Costolo on Wednesday about his company's new policy to allow governments to censor some tweets.
"We understand that Twitter has an obligation to comply with legal requests that do not violate human rights, and we appreciate that you are taking steps to minimize the impact of censorship," the lawmakers wrote. "However, your announcement leaves important questions unanswered."
The lawmakers asked Twitter how it determines whether it must comply with a government's request to censor a tweet and whether it considers if the request violates international human-rights law.
They urged Twitter to join the Global Network Initiative, a voluntary code for tech companies to protect human rights.