The man was intercepted by personnel from the US Embassy in Moscow and handed over to local authorities. There were no injuries and John Sullivan was not at the residence at the time.
Spokeswoman at the US Embassy in Moscow, Rebecca Ross, said: “At approximately 16:20, a Russian national in a vehicle breached the perimeter at Spaso House, the U.S. Ambassador’s residence in Moscow.
“He was intercepted by Embassy personnel and turned over to local authorities.
“Amb Sullivan was not home at the time, and no one was injured.”
No further information about the security incident has been released.
Mr Sullivan was nominated by Donald Trump as the US Ambassador to Russia in October 11 2019.
He was confirmed by the Senate on December 12 2019.
Mr Sullivan was sworn in by Secretary of State Mike Pompeo on December 23 2019.
Mr Pompeo tweeted at the time: “Honored to swear in John Sullivan as the new U.S. Ambassador to #Russia today.
“I’m confident John will effectively lead the effort to strengthen cooperation and build a constructive relationship with Russia.”
Mr Sullivan was Deputy Secretary of State from May 2017 to December 2019.
He served as acting Secretary of State in April 2018.
Mr Sullivan replaced Jon Hunstman as the US Ambassador to Russia.
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