Microsoft announced Friday a group tied to the Iranian government tried to hack email accounts belonging to a U.S. presidential campaign.

The group, which Microsoft calls Phosphorous, made more than 2,700 attempts to identify email accounts associated with its customers over a 30-day period between August and September, the company said. Phosphorous, which Microsoft believes is from Iran and linked to the Iranian government, then attempted to attack 241 of those accounts.

Microsoft said the accounts targeted were associated with a U.S. presidential campaign, current and ex-government officials, journalists, and prominent Iranians who do not live in the country.

The group compromised four accounts, though they did not belong to the presidential campaign or government officials, The customers were notified by Microsoft of the hack.

Microsoft did not identify the presidential campaign targeted, but according to Reuters, the hackers tried to compromise President Trump's reelection campaign, though they did not succeed. The Trump campaign's website is the only one among the current slate of candidates tied to Microsoft's cloud email service.

Tim Murtaugh, the campaign's communications director, said it had "no indication that any of our campaign infrastructure was targeted."

According to Microsoft, Phosphorous tried to use “a significant amount” of personal information to identify the accounts and hack them.

“This effort suggests Phosphorous is highly motivated and willing to invest significant time and resources engaging in research and other means of information gathering,” Tom Burt, Microsoft’s corporate vice president, said in a post on the company’s website.

Microsoft decided to disclose the cyberthreats because it believes it’s important the public and private sector “are increasingly transparent about nation-state attacks and efforts to disrupt democratic processes” and to encourage others to protect themselves online, Burt said.

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