Ms. Greene, Republican of Georgia, has been an outspoken opponent of vaccines and masks as tools to curb the pandemic. In tweets on Sunday and Monday, she argued that Covid-19 was not dangerous for people unless they were obese or over age 65, and said vaccines should not be required…

Twitter said Ms. Greene’s tweets were misinformation, and it barred her from the service until Tuesday. “We took enforcement action on the account @mtgreenee for violations of the Twitter Rules, specifically the Covid-19 misleading information policy,” a Twitter spokesman said. The company also added labels to Ms. Greene’s posts about the vaccines, calling them “misleading” and pointing to information about the safety of the inoculations.

In a statement, Ms. Greene said Silicon Valley companies were working with the White House to attack free speech. “These Big Tech companies are doing the bidding of the Biden regime to restrict our voices and prevent the spread of any message that isn’t state-approved,” she said.