Russia is backing Donald Trump, China is supporting Joe Biden and Iran is seeking to sow chaos in the US presidential election, a top intelligence official has warned in a sobering assessment of foreign meddling. The statement on Friday by William Evanina, director of the National Counterintelligence and Security Center, raises fears of a repeat of the 2016 election, when Russia manipulated social media to help Trump and hurt his opponent Hillary Clinton. “Russia is using a range of measures to primarily denigrate former Vice President Biden and what it sees as an anti-Russia ‘establishment’,” Evanina said. “This is consistent with Moscow’s public criticism of him when he was Vice President for his role in the Obama Administration’s policies on Ukraine and its support for the anti-Putin opposition inside Russia.” Evanina identified Andriy Derkach, a pro-Russia Ukrainian politician, as “spreading claims about corruption – including through publicized leaked phone calls” to attack Biden’s campaign. The Washington Post reported that Derkach has met repeatedly with Trump’s personal lawyer, Rudy Giuliani, who has pushed conspiracy theories about the former vice-president. Evanina also warned that some “Kremlin-linked actors” were spreading false claims about corruption to undermine Biden, while others were trying to “boost President Trump’s candidacy via social media and Russian television”. Evanina, the top intelligence official monitoring threats to the election, is a Trump appointee. His statement lists China before Russia but presents less specific evidence of direct interference by Beijing. “We assess that China prefers that President Trump – whom Beijing sees as unpredictable – does not win re-election,” Evanina said. “China has been expanding its influence efforts ahead of November 2020 to shape the policy environment in the United States, pressure political figures it views as opposed to China’s interests, and deflect and counter criticism of China.” He added: “Beijing recognizes that all of these efforts might affect the presidential race.” Evanina highlighted China’s criticism of Trump’s handling of the coronavirus pandemic, the closure of China’s consulate in Houston and the White House responses to Chinese actions in Hong Kong and the South China Sea. On Friday, the US imposed sanctions on Hong Kong’s chief executive, Carrie Lam, and 10 other senior officials. Trump has also ordered crackdowns on the Chinese owners of the popular apps TikTok and WeChat. Iran, meanwhile, was seeking to undermine US democratic institutions and Trump, and to divide the country ahead of the 2020 elections, Evanina’s statement said. “Iran’s efforts along these lines probably will focus on on-line influence, such as spreading disinformation on social media and recirculating anti-US content. Tehran’s motivation to conduct such activities is, in part, driven by a perception that President Trump’s reelection would result in a continuation of US pressure on Iran in an effort to foment regime change.” Trump pulled the US out of a nuclear deal agreed by Barack Obama and imposed various sanctions on Tehran. The anti-Trump pressure group National Security Action denied that China’s public actions rose to the level of Russia’s covert election interference. “Jarringly, the statement attempted to minimize what Russia is doing – again attacking our democracy in a bid to secure Trump’s reelection – by comparing it to China’s public criticism of the administration’s recent punitive measures against Beijing,” a spokesperson, Ned Price, said. “Any interference in our democracy is unacceptable, but there is no equivalence between the two efforts.” A hacking and social media campaign by Russia in 2016 is credited by US intelligence with helping Trump to victory. It triggered the special counsel Robert Mueller’s investigation, which described Russian meddling but did not conclude that there had been direct collusion by Trump or his campaign. The November election is already under siege from the coronavirus pandemic, concerns over whether the system can handle a surge in mail-in voting and constant attacks by Trump on the integrity of the process. Evanina warned that foreign adversaries may try to interfere with election systems by trying to sabotage the voting process, stealing election data or questioning the validity of results: “Foreign efforts to influence or interfere with our elections are a direct threat to the fabric of our democracy.” The report raised concern on Capitol Hill. Marco Rubio and Mark Warner, the top Republican and Democrat on the Senate intelligence committee, said they “encourage political leaders on all sides to refrain from weaponizing intelligence matters for political gain”. Mitch McConnell, the Republican Senate majority leader, said: “It is no surprise our adversaries have preferences in our elections. Foreign nations have tried to influence our politics throughout American history. As Director Evanina’s statement makes clear, Russian malign influence efforts remain a significant threat. But it would be a serious mistake to ignore the growing threats posed by China and Iran.”