A hacking group that appears to be linked to the Iranian government has targeted a US presidential campaign but did not succeed, Microsoft Corp said on Friday. Microsoft saw "significant" cyber activity by the group that also targeted current and former US government officials, journalists covering global politics and prominent Iranians living outside Iran, the company said in a blog post. Corporate vice president for security Tom Burt said in a blog post Friday that owners of four accounts that were successfully breached have been notified. He said those accounts that were compromised were not related to US campaigns or officials. In a 30-day period between August and September, the group, called "Phosphorous" by the company, made more than 2,700 attempts to identify consumer email accounts belonging to specific customers and then attacked 241 of those accounts. Microsoft did not identify the election campaign whose network was targeted by Phosphorous hackers. Nineteen Democrats are seeking their partys nomination to run against President Donald Trump in the November 2020 election. Hacking to interfere in elections has become a concern for governments especially since United States intelligence agencies concluded that Russia ran an operation to disrupt the American democratic process in 2016 to also help then-Republican candidate Trump become president. Microsoft has been tracking Phosphorus since 2013 and said in March that it had received a court order to take control of 99 websites the group used to execute attacks.