Russian, China, Iran and other countries are engaged in continuous efforts to influence American policy and voters in the upcoming elections and beyond, national security officials say.

“We are concerned about ongoing campaigns by Russia, China and other foreign actors, including Iran, to undermine confidence in democratic institutions and influence public sentiment and government policies,” the officials said in a joint statement.

“These activities also may seek to influence voter perceptions and decision-making in the 2018 and 2020 US elections.”

The two-page statement about foreign influence in US elections was issued just weeks before the November 6 elections by the Office of the Department of National Intelligence, the Justice Department, the FBI and the Department of Homeland Security.

Other countries are using social media to amplify divisive issues in American society, sponsor content in English-language media, such as Russia’s RT and Sputnik news outlets, the statement said.

They also distribute propaganda and plant disinformation against political candidates, the departments said.

They statement did not provide specific examples of foreign interference.

The agencies said they currently do not have any evidence that voting systems have been disrupted or compromised in ways that could result in changing vote counts or hampering the ability to tally votes in the midterms, which are fewer than 20 days away.

“Some state and local governments have reported attempts to access their networks, which often include online voter registration databases, using tactics that are available to state and nonstate cyber actors,” they said.

But so far, they said state and local officials have been able to prevent access or quickly mitigate these attempts.

President Donald Trump has often cast doubt on US intelligence findings that Russia interfered with the 2016 election, as special counsel Robert Mueller investigates potential ties between Russia and Trump’s campaign.

But President Trump recently accused China of meddling in the midterms, and Vice President Mike Pence said in a speech this month that Russia’s actions in 2016 pale in comparison to the covert and overt activities China is taking to interfere in the US midterm elections and counter the president’s tough trade policies against Beijing.

China has denied that it is interfering in US affairs.

Deputy Foreign Minister Sergei Ryabkov said recently that Russia has no intention to interfere in the midterm elections in the US or meddle elsewhere.