Facebook FB on Tuesday removed 32 “inauthentic” accounts it said mimicked Russian-linked actions to incite social and political tension, now just 98 days ahead of the midterm elections.

The company said it deleted 17 personal profiles, eight pages and seven Instagram accounts created between and . The accounts were involved in “coordinated inauthentic behavior,” misleading other social media users about their identities.

Facebook said it’s unclear who is behind the accounts, but said it took similar action against accounts created by the Russian-based Internet Research Agency.

In February, the Department of Justice indicted the IRA for conspiracy to commit wire and bank fraud, and aggravated identity theft. Deputy Attorney General Rod Rosenstein said the organization conducted “information warfare” against the United States to spread distrust toward the candidates and the U.S. political system in general. In some cases, the IRA had fictitious social media accounts organize rallies in support of and in opposition to President Donald Trump in the same city and on the same day.

Facebook said the accounts removed Monday went to greater links than did past IRA-linked accounts to obscure their true identities.

“We believe this could be partly due to changes we’ve made over the last year to make this kind of abuse much harder,” the company said in a blog post announcing the removal of the accounts. “But security is not something that’s ever done. We face determined, well-funded adversaries who will never give up and are constantly changing tactics.”

Nathaniel Gleicher, head of Facebook cybersecurity policy, said more than 290,000 accounts followed at least one of the eight phony pages, which had names like Aztlan Warriers, Black Elevation and Resisters. The accounts created more than 9,500 posts and ran about 150 ads worth about $11,000 on Facebook and Instagram.

The fictitious pages created about 30 events, one of which had about 4,700 people interested in attending. One event scheduled to be held in August in Washington, D.C., enlisted the support of five legitimate pages as co-hosts.

Facebook said it notified law enforcement and Congress about the removed accounts.