Officers used firearms and a Taser before arresting a man on suspicion of attempted murder.
Police attended at approximately 09:50 BST after reports of antisocial behaviour involving a car in Holland Park, W11.
When officers arrived on the scene, a car was “driven at them”, the Met said.
‘Forced to open fire’
Describing the events of Saturday morning, the Ukrainian embassy said that after seeing the ambassador’s car being targeted, police “blocked up” the other vehicle.
“Nevertheless, despite the police actions, the attacker hit the ambassador’s car again,” the embassy said.
It added police were “forced to open fire on the perpetrator’s vehicle”.
Following his arrest, the man was taken to a London hospital as a precaution before being taken to a central London police station.
Eyewitnesses saw the man “ramming” the embassy car.
Darcy Mercier, who lives across the road from the Ukrainian embassy, told the BBC the man arrived in the street around 07:00 and was “blasting music”.
Mr Mercier said he approached the man and asked him to turn the music off but was ignored.
“He sat in the middle of the street for over two hours. I was out on my terrace when he started ramming the embassy car,” he added.
Chief Superintendent Andy Walker, from the Met’s Specialist Firearms Command, said: “As is standard procedure, an investigation is now ongoing into the discharge of a police firearm during this incident.”
Adding: “I would like to pay tribute to the officers involved in this incident who responded this morning and put themselves in harm’s way as they do every day to keep the people of London safe.”