Twitter added labels to two tweets from Trump for “encouraging people to potentially vote twice,” the company said. Trump suggested on Twitter Thursday morning that people vote in person as well as by mail to be “ASSURED THAT YOUR PRECIOUS VOTE HAS BEEN COUNTED.”

The same post was also flagged on Facebook, where the company added a label that directed users to its voting information center. “Voting by mail has a long history of trustworthiness in the U.S. and the same is predicted this year,” Facebook wrote on the label appended to the president’s post.

Trump has criticized mail-in ballots, suggesting the system will lead to a fraudulent or rigged election. Many Americans are expected to vote by mail this year due to health concerns driven by the coronavirus.