Facebook has suspended three networks of Russian accounts that it says attempted to interfere in the domestic politics of eight African countries, and were tied to a Russian businessman accused of meddling in past U.S. elections.

The campaigns used almost 200 fake and compromised accounts to target people in Madagascar, Central African Republic, Mozambique, Democratic Republic of Congo, Cote d’Ivoire, Cameroon, Sudan and Libya, Facebook said on Wednesday.

The accounts created are said to have amassed more than 1 million followers.

All the networks were connected to "entities associated with Russian financier Yevgeniy Prigozhin," a Russian catering tycoon indicted by U.S. special prosecutor Robert Mueller as the backer of an alleged Russian effort to sway elections in the United States with covert social media campaigns.

Prigozhin and lawyers representing him did not immediately respond to a request for comment about the latest Facebook accusations. He has previously denied any wrongdoing.

In some of the African countries, the Russian-run networks worked with local citizens to better disguise their origins and target internet users, said Nathaniel Gleicher, Facebook’s head of cyber security policy.

"There’s sort of a joining of forces, if you will, between local actors and actors from Russia," he told Reuters. "It appears that the local actors who are involved know who is behind the operation."

The giant social media platform however declined to identify which local people or organisations had worked with the accounts or which companies it had connected to the activity and Prigozhin, nicknamed "Putin’s cook" by Russian media because of banquets he has organised for Russian leader Vladimir Putin.

Facebook, Twitter Inc and Alphabet Inc’s Google have vowed to step up the fight against political manipulation of their platforms after facing fierce criticism for failing to counter alleged Russian interference in the 2016 U.S. election.