(CNN) A group of North Korean hackers is believed to be actively targeting US businesses and "critical infrastructure," a report released this week by cybersecurity firm McAfee said.

McAfee said it found that the North Korean hackers have tried to infiltrate nearly 80 business in critical sectors like finance, telecommunications, energy and defense around the world. Governments themselves were also targeted, McAfee said.

The hacking is believed to have continued during US President Donald Trump's summit with Kim Jong Un. The largest number of recent attacks primarily target Germany, Turkey and the United Kingdom as well as the United States, McAfee said.

Pyongyang is believed to operate some of the most sophisticated hacking cells in the world, though the North Korean government has long denied any wrongdoing.

McAffee said it partnered with a "government entity" in its investigation, though it declined to reveal which government it worked with.

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