Director of National Intelligence Dan Coats speaks during the daily press briefing at the White House. Picture: AP Photo/Evan Vucci

Washington - The threat of foreign influence in US elections is pervasive and ongoing, top Trump administration officials said Thursday as they described a strategy they have developed to counter it.

The threat is coming not only from Russia but other governments, the officials said at the White House. In response, the United States is stepping up its defences not only in light of midterm elections in November but also to ensure the integrity of the 2020 presidential election.

"Our focus here today is simply to tell the American people we acknowledge the threat it is real, it is continuing and we are doing everything we can to have a legitimate election that the American people can have trust in," Director of National Intelligence Dan Coats said.

Coats joined Secretary of Homeland Security Kirstjen Nielsen, FBI Director Christopher Wray, National Security Adviser John Bolton and General Paul Nakasone at the briefing.

The officials stressed that the administration is taking steps to actively confront cybersecurity threats, including attempts to influence elections through social media.

The government's show of force against election meddling comes two days after Facebook said it had identified 32 accounts and pages that it said were part of a "coordinated" effort by people who sought to hide their identities to spread information or influence users' political beliefs.

Facebook added that some of the findings were consistent with activity by the Russia-based Internet Research Agency ahead of the 2016 election. The social media giant remains under pressure over inflammatory content, coordinated disinformation campaigns and data breaches on its platform.

The Trump administration officials who briefed reporters on Thursday said attempts to hack into databases of voter rosters and election funding are among the other threats.

While Coats said Russia's efforts, in particular, are widespread, including some that are Kremlin-backed and others that are operated by rogue individuals, authorities have not seen the kind of robust efforts witnessed in 2016.

However, the intent - to "drive a wedge and undermine our democratic values" - is the same, he said.

US officials in recent weeks have been sounding the alarm about a continuation of the type of cyber election interference carried out by Russia in 2016. US intelligence agencies concluded shortly after the presidential election that year that Russia's intelligence services conducted cyber operations against both major US political parties.

Bolton denied that the White House had been inconsistent in its messages on the meddling, and said President Donald Trump has been determined to prevent Russian and other foreign influence in elections.

"Since January 2017, the president has taken decisive action to defend our election systems from meddling and interference," he said, citing sanctions against Russians and the expulsion of Russian diplomats.

He also said the issue was raised during Trump's expanded bilateral meeting last month in Helsinki with Russian President Vladimir Putin. Trump was heavily criticized for not chastising Russia for the interference at a news conference with Putin.

Putin has repeatedly rejected the US allegations that Russia interfered in the 2016 election.

Wray said some examples of what law enforcement have seen is the targeting US officials through traditional intelligence, criminal efforts to suppress voting and illegal campaign financing. In addition, they have encountered cyber attacks against voting infrastructure and computer intrusions targeting elected officials.

The efforts also include covertly manipulating news stories, spreading disinformation and attempts to escalate divisive issues.

A special task force set up by the FBI has sent people to all 56 FBI field offices across the country and currently has "open investigations with a foreign influence nexus spanning ... FBI field offices across the country."

The problem is not just an election cycle threat, Wray said.

"Our adversaries are trying to undermine our country on a persistent and regular basis, whether it's election season or not."