Jeff Seldin contributed to this report.
Microsoft said hackers linked to the Iranian government targeted a U.S. presidential campaign, but were not successful.
The company said in a blogpost Friday that the hackers attempted to penetrate 241 accounts, including a U.S. presidential campaign, current and former U.S. government officials, media targets and prominent expatriate Iranians.
It said the hackers were successfully able to access four accounts, but Microsoft said none of those accounts belonged to a campaign or any current or former government officials.
Microsoft did not identify the election campaign whose network was targeted by the hackers.
Chris Krebs, director of the Department of Homeland Security's Cybersecurity and Infrastructure Security Agency, said in a statement to VOA that his agency is aware of the report by Microsoft and "we are working with them to assess and mitigate impacts."
"While much of this activity can likely be attributed to run-of-the-mill foreign intelligence service work, Microsoft's claims that a presidential campaign was targeted is yet more evidence that our adversaries are looking to undermine our democratic institutions," he said.
A computer network used by 2016 Democratic presidential candidate Hillary Clinton's campaign was hacked during that election.
The latest attacks by a group that Microsoft dubbed "Phosphorous" occurred during a 30-day period between August and September. Microsoft said the attacks were not technically sophisticated but did say the hackers researched their targets and tried to use personal information to access the accounts.