"No one of the embassy staff were injured", the embassy said.
The embassy, located in Holland Park in west London, said the official vehicle of the Ambassador of Ukraine to the UK, Natalia Galibarenko, was attacked on Saturday morning at around 10am.
Officers attempted to block the vehicle, then fired shots with Tasers and live bullets after the Mercedes again drove into Galibarenko's auto - and also into police - at about 10am yesterday.
London Metropolitan Police said "armed and unarmed officers were deployed" to the scene at 8:30 a.m. (3:30 a.m. ET) after "reports of a auto in collision with a number of parked vehicles near the Ukrainian Embassy".
"On arrival at the scene, a vehicle was driven at police officers", the force said in a statement.
"He has been taken to a central London hospital as a precaution", the statement said, adding that the man had not been injured. Police did not report any injuries to the suspect.
Some reports suggested there were shots from the auto that hit the ambassador's vehicle, but the embassy said only the British police opened fire.
Police say the incident is not being treated as related to terrorism.
One witness, who works at a nearby shop, said she heard shots fired twice.
A silver vehicle outside the embassy was the subject of a forensic officer's investigation on Saturday afternoon.
A spokesperson for the embassy told the Telegraph that since the perpetrator posed a threat to the ambassador, an armed police officer had to open fire and shoot at the driver through the window an unknown number of times.
The black vehicle was heavily scuffed on its right-hand side.
A Met police spokesman said the incident took place on Saturday morning and was not ongoing.
Meanwhile, the directorate of professional standards, which investigates complaints against the professional conduct of officers in the Met, has been informed of the incident.