They covered their tracks, using software to camouflage their internet traffic. They created Facebook pages for anti-Trump culture warriors, Hispanic activists and fans of alternative medicine. And they organized protests in coordination with real-world political groups.

The people behind an influence campaign ahead of this year’s elections, which Facebook disclosed on Tuesday, copied enough of the tactics used by Russians in the 2016 races to raise suspicion that Russia was at it again. But the new efforts also revealed signs of a maturing adversary, adapting and evolving to better disguise itself, while also better imitating real activists.

The coordinated activity — a collection of memes, photos and posts on issues like feminist empowerment, indigenous rights and the Immigration and Customs Enforcement agency — show the enormity of the challenge ahead of Facebook, as it tries to weed out impersonators. As the forces behind the accounts become harder to detect, the company is left to separate the ordinary rants and raves of legitimate users from coordinated, possibly state-backed attempts to sway public opinion.

“This is not a one-time event limited to the 2016 election,” said Michael Posner, the director of the Center for Business and Human Rights at New York University’s Stern School of Business, which recently published a report about Russian influence campaigns. “It’s a daily drumbeat. These are entities trying to disrupt our democratic process by pushing various forms of disinformation into the system.”