The X account of Yulia Navalnaya, widow of Russian opposition leader Alexei Navalny, was briefly suspended on Tuesday due to what the social media company said was an error caused by a system to prevent manipulation and spam.
"Our platform's defense mechanism against manipulation and spam mistakenly flagged @yulia_navalnaya as violating our rules," X said in a statement.
"We unsuspended the account as soon as we became aware of the error, and will be updating the defense."
Navalnaya, who has said she wants to continue her late husband's political struggle against President Vladimir Putin, opened the account on Monday.
It has so far attracted more than 150,000 followers and a video statement she posted on it on Monday has been viewed nearly 5 million times.