U.S. Representative Adam Schiff on Thursday called on Facebook and Amazon to provide a more thorough explanation of their efforts to mitigate the spread of COVID-19 vaccine misinformation.
"Despite some concrete and positive steps previously taken, these companies owe both the public and the Congress additional answers about the exponential and dangerous proliferation of misinformation," Schiff, chairman of the House intelligence committee, said in a statement after sending letters to the companies.
U.S. technology companies have come under fire from the Biden administration and other critics for the alarming spread of vaccine misinformation that they say is slowing inoculation in the country and increasing hostility to vaccines.
Other companies, including YouTube, Twitter and Alphabet Inc's Google, have also faced criticism for allowing false information on COVID-19, including vaccines, to proliferate.
Representatives for Facebook and Amazon could not be immediately reached for comment on Schiff's query.
Facebook last month said it had removed dozens of vaccine misinformation "superspreaders".