SAN FRANCISCO (Reuters) – Twitter on Thursday said it was removing hundreds of thousands of accounts tied to a Beijing-backed influence operation that deceptively spread messages favorable to the Chinese government, including about the coronavirus.

The social media company suspended a core network of 23,750 highly active accounts, as well as a larger network of about 150,000 “amplifier” accounts, which it said were used to boost the core accounts’ content.

Twitter, along with researchers who analyzed the accounts, said the network had not gained much traction, and instead created an echo chamber of fake accounts.

The company said the network had links to an earlier Chinese state-backed operation dismantled last year by Twitter, Facebook and Google’s YouTube that had been pushing misleading narratives about political dynamics in Hong Kong.

The new operation likewise focused heavily on protests in Hong Kong, but also promoted messages about the coronavirus pandemic, exiled Chinese billionaire Guo Wengui and Taiwan, the researchers said.

Renee DiResta, research manager at the Stanford Internet Observatory, said the network’s activity around the coronavirus ramped up in late January, when the outbreak started to spread beyond China, and spiked in late March.

It largely praised China’s response to the virus, while also using the pandemic to antagonize the United States and activists in Hong Kong, she said.

Open-source researchers at Graphika and Bellingcat had earlier flagged the re-emergence of what some dubbed the “Spamouflage Dragon” network, after it went dormant following the tech companies’ coordinated takedowns last summer.

The U.S. State Department also said in early May it had found a new network of inauthentic Twitter accounts with “highly probable” linkages to the Chinese Communist Party that were disseminating false claims about the coronavirus.

Twitter pushed back on the State Department’s assertions at the time, saying the 5,000 accounts the agency identified included non-governmental organizations and journalists, and largely were not expressing support for Chinese positions.