WASHINGTON (Reuters) - Facebook Inc said on Wednesday it has declined an invitation to testify at a U.S. House of Representatives hearing Thursday on filtering practices by social media companies, a company spokesman said.

A man poses with a magnifier in front of a Facebook logo on display in this illustration taken in Sarajevo, Bosnia and Herzegovina, December 16, 2015. REUTERS/Dado Ruvic

The company said that even though it will not appear, it looks “forward to a continuing dialogue with members of the committee about Facebook’s strong commitment to being a platform for all voices and ideas.”

Alphabet Inc and Twitter Inc have also been invited to testify at the House Judiciary Committee hearing, but have not said whether they will appear and did not respond to repeated inquiries on Wednesday. Some Republicans have criticized social media companies for censoring some conservative viewpoints, a charge the firms have denied.

A spokesman for Democrats on the House Judiciary Committee said Twitter and Alphabet were not expected to testify. A spokeswoman for the committee’s Republican majority did not immediately comment.

Facebook Chief Executive Mark Zuckerberg testified for more than 10 hours earlier this month before Congress and faced numerous questions about whether the company was biased against some political points of view.

Thursday’s hearing will also include testimony from Representative Marsha Blackburn, a Tennessee Republican, who in October was initially barred by Twitter from paying to promote a video of her campaign announcement for Senate that included a line that said she had worked to “stop the sale of baby body parts.”

Twitter said in October it had blocked promoting the video because of “potentially inflammatory” language but reversed itself. The company said it works to “balance protecting our users from potentially distressing content while allowing our advertisers to communicate their messages.”

The hearing is also set to include two African-American sisters, Lynnette Hardaway and Rochelle Richardson, popularly known as “Diamond and Silk,” who are strong supporters of President Donald Trump and his presidential campaign.

The sisters said in a statement earlier this month that Facebook had sent them an email saying that, after a review, their content had “been determined unsafe to the community.”

Zuckerberg was asked by Republican Representative Joe Barton at a hearing earlier this month about why Facebook was “censoring conservative bloggers such as Diamond and Silk?”

Zuckerberg responded that “in that specific case, our team made an enforcement error and we have already gotten in touch with them to reverse it.”