Officers opened fire in west London on Saturday morning during an incident involving a car which was colliding with vehicles, the Metropolitan Police has said.
The Ukrainian embassy said its ambassador’s vehicle was “deliberately rammed” as it sat parked outside the building in Holland Park.
When officers arrived on the scene, a car was “driven at them”, the Met said.
Officers used firearms and a Taser before arresting a man in his 40s.
Police said the uninjured man was “taken to a central London hospital as a precaution”.
They added that the situation was neither ongoing nor being treated as terror-related.
The Met said its officers arrived at the scene just before 10:00 GMT after “reports of antisocial behaviour involving a car”.
Describing the events of Saturday morning, the Ukrainian embassy said that after seeing the ambassador’s car being targeted, police “blocked up” the attacker’s 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”.
The embassy said none of its staff had been injured and that police were now investigating “the suspect’s identity and motive for the attack”.
A woman who works at a nearby shop told the Press Association she heard shots fired twice between 10:00 and 11:00.
The woman, who did not wish to be named, said officers arrived “very quick”, adding: “I saw many police cars coming.”
Local resident Heather Feiner, originally from the US, added: “From the time I heard the shots until I got to the window, which took about 15 seconds, all these police cars were already there.
“I could see a police officer that fired the shots. I could see them pointing their gun at the car.
“From what I could see [the suspect] didn’t appear to be struggling at that point.”
Ch Supt 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.
“While this takes place, I would like to pay tribute to the officers involved this morning who responded swiftly to this incident and put themselves in harm’s way, as they do every day, to keep the people of London safe.”