Shots have been fired by firearms officers in the Holland Park area of west London, the Metropolitan Police have said.
A statement on the Ukrainian Embassy website said the official vehicle of the Ambassador of Ukraine to the United Kingdom was deliberately rammed as it sat parked in front of the Embassy of Ukraine's building at around 10am.
It added: "The police were called immediately, and the suspect's vehicle was blocked up. Nevertheless, despite the police actions, the attacker hit the Ambassador's car again. In response, the police were forced to open fire on the perpetrator's vehicle.
"The culprit was apprehended and taken to a police station. No one of the Embassy staff were injured.
"The police are investigating the suspect's identity and motive for the attack."
A woman who works at a nearby shop said she heard shots fired twice between 10am and 11am on Saturday.
The woman, who did not wish to be named, said officers arrived "very quick", adding: "I saw many police cars coming."
A Met Police spokesman said the incident took place on Saturday morning and was not ongoing.
