The FBI has launched an investigation into attempts to hack Kamala Harris's and Donald Trump's presidential campaigns.
The details about an alleged hack of former president Trump's campaign emerged over the weekend, with officials blaming Iran.
The Trump campaign has said the alleged hack was intended to interfere with the upcoming 2024 election and "sow chaos" in America's democratic process.
It comes about eight years after the last US election marred by foreign interference.
Here's what we know so far.
What happened?
Over a few weeks, US media organisations including Politico, the New York Times and the Washington Post reported receiving emails from a person who called themselves "Robert" and said they were offering internal documents from Trump's campaign.
The documents were allegedly a research dossier on Republican vice-presidential nominee JD Vance but it was dated months before he was selected to be Trump's running mate.
None of those media outlets reported what was in the internal documents.
Politico asked the man who called himself Robert how he obtained the documents.
This was his response:
"I suggest you don't be curious about where I got them from. Any answer to this question, will compromise me and also legally restricts you from publishing them," Politico reported.
Washington Post executive editor Matt Murray said news outlets weren't going to jump at any hack that might come their way just because the documents were marked with the exclusive label.
"All of the news organisations in this case took a deep breath and paused, and thought about who was likely to be leaking the documents, what the motives of the hacker might have been and whether this was truly newsworthy or not," he said.
Microsoft recently issued a report detailing the emergence of Iranian actors in the US election. The company said that over the past three US election cycles, Iranian cyber influence had been a consistent feature.
"Iran's operations have been notable and distinguishable from Russian campaigns for appearing later in the election season and employing cyber attacks more geared toward election conduct than swaying voters," the report said.
"Recent activity suggests the Iranian regime — along with the Kremlin — may be equally engaged in election 2024."
The FBI released a short statement that said: "We can confirm the FBI is investigating this matter."
Is the Harris campaign also being targeted by the alleged Iran hack?
There have been reports in the US that at least three members of the Biden-Harris campaign were targeted with phishing emails but those attempts were unsuccessful and occurred before Ms Harris took over the Democratic nomination.
"Our campaign vigilantly monitors and protects against cyber threats, and we are not aware of any security breaches of our systems," a spokesperson for the Harris campaign said.
But Ms Harris's campaign did not address whether it had identified any attempts from foreign actors.
What's been the reaction?
Trump campaign spokesperson Steven Cheung said the attempted hack in June identified in the Microsoft report coincided closely with the selection of JD Vance as the former president's running mate.
"The Iranians know that President Trump will stop their reign of terror just like he did in his first four years in the White House," Mr Cheung said.
"[It is] intended to interfere with the 2024 election and sow chaos throughout our democratic process."
But the allegations regarding Iran being part of the attempted hack have been denied by a spokesperson for Iran's permanent mission to the United Nations.
"We do not accord any credence to such reports," the spokesperson said.
"The Iranian government neither possesses nor harbours any intent or motive to interfere in the United States presidential election."
What do cybersecurity experts think of the alleged hack?
RMIT University Centre for Cyber Security director Professor Matthew Warren said foreign interference could take a few forms, from trying to steal information to attempting to change public perception through disinformation.
"In terms of the Trump campaign, there have already been some photos that have allegedly been released showing some of the candidates in a sort of an embarrassing situation," he said.
Professor Warren said countries such as Iran, Russia and China, which have faced allegations of foreign interference, have very different motivations and political goals.
"Some countries may just want to be after data, information, other countries may be trying to manipulate the outcome of an election … this is what makes it more complex," he said.
He said he had noticed Russian-backed foreign interference was designed to create chaos and disengage voters.
"In terms of the Iranians, they know that a Trump presidency would be more anti-Iranian and pro-Israeli. So what they're trying to do is manipulate the election outcome to potentially stop a Trump election through disinformation," he said.
"In terms of the Chinese, they're just after information that they may not do anything with at the moment, but they would want to use it maybe in the future to help define their strategic narratives or strategic policies."
AP/ABC
