Russia, China and Cuba have all launched influence operations designed to help or hurt candidates in specific congressional races. Without giving specifics about the number of affected races, an official from the Office of the Director of National Intelligence said Monday that all three countries have zeroed in on races where they believe they have a national security interest at stake.

The warning from intelligence officials comes during a particularly tight battle for the House and Senate, where control could be decided by just a handful of races. While much of the attention has focused on attempts by foreign adversaries to influence the presidential race, Monday’s warning underscores the threat that online disinformation also poses in state and local contests.

Leaders in Russia, China and Cuba understand the American political system well enough to recognize that this year’s close elections create good conditions for the use and spread of disinformation, said the official, who briefed reporters on condition of anonymity under rules set by the office of the director.

Foreign adversaries have also targeted some races even further down the ballot, including statewide offices and state legislative campaigns, the official said.

Moscow’s goal is to erode support for congressional candidates who favor assisting Ukraine in its war with Russia. Officials wouldn’t say which candidates were targeted, but it’s likely that the Kremlin’s effort is intended to hurt Democrats and centrist Republicans who have supported Ukraine.

China has targeted candidates from both parties based on their stance on issues of key importance to Beijing, including support for Taiwan. Officials said they have observed Chinese disinformation agencies focusing on candidates in “tens” of races.

Cuba’s government has mounted a narrower operation aimed at boosting candidates it believes would favor better relations with the island, such as reduced economic sanctions.

Influence operations can include false or exaggerated claims and propaganda designed to mislead voters about specific candidates, issues or races. It can also include social media posts or other digital content that seeks to suppress the vote through intimidation or by giving voters false information about election procedures.

Along with cyberattacks on election systems, influence operations that stoke distrust and divisiveness are a critical threat facing the 2024 election, national security officials have said.

State and local authorities have invested heavily in securing the vote that last week, Jen Easterly, director of the U.S. Cybersecurity and Infrastructure Security Agency, told The Associated Press there is no way a foreign adversary could alter the overall results.

Disinformation can be a harder threat to quantify. Foreign adversaries create networks of fake websites and social media accounts mimicking Americans, and then work to amplify divisive and incendiary claims about contentious debates like immigration, the economy or the federal government’s response to disasters.

Officials in Russia, China, Iran and Cuba have all rejected accusations that their governments are trying to interfere with the U.S. election, despite indications that the use of disinformation designed to influence the outcome of this year’s elections is increasing.

When foreign governments target a specific candidate, office or organization with election information they are often given what’s called a defensive briefing by intelligence officials. While ODNI won’t say how many defensive briefings they have delivered so far this election cycle, they say the number is three times higher than the previous cycle.

In the presidential race, intelligence officials have concluded that Russia supports Trump, who has criticized Ukraine and the NATO alliance while praising Russian President Vladimir Putin. They have assessed that China is taking a neutral stance in the race between the Republican former president and Vice President Kamala Harris, a Democrat.

Iran opposes Trump’s reelection, intelligence officials have said, seeing him as more likely to increase tension between Washington and Tehran. Trump’s administration ended a nuclear deal with Iran, reimposed sanctions and ordered the killing of Iranian Gen. Qassem Soleimani, an act that prompted Iran’s leaders to vow revenge.

Last month federal authorities charged three Iranian men for their alleged involvement in Iran’s hacking of Trump’s campaign. Iran later offered the material to Trump’s Democratic opponent, but no one replied.

Officials said Monday they have seen no indications that Iranian disinformation is targeting down ballot races so far in 2024.