A driver was killed ramming his car into the gate of the Russian embassy in Bucharest early on Wednesday, police in the Romanian capital said in a statement.
A video recorded before firefighters arrived showed the front of the car in flames as it remained wedged in the gate.
It was unclear whether the crash was an accident or deliberate.
In recent weeks, several Russian embassies elsewhere in Europe have been targeted by protesters angered by the invasion of Ukraine.
Police said they were investigating and did not release the identity of the driver.
Romania said on Tuesday it would expel 10 Russian diplomats who are not acting in accordance with international rules, joining other European countries to have done so in recent days.
The moves coincide with outrage across the continent over reports of the discovery of mass graves and of civilian killings in the Ukrainian town of Bucha following the retreat of Russian soldiers.
"Romanian authorities have decided to declare personae non-gratae on Romanian territory ten people working at the Russian embassy in Bucharest, given that their actions ... contravene the Vienna Convention," the ministry said in a statement.
It added the ambassador had been called to the ministry to be notified of the decision.
"The ministry has reiterated it firmly condemns the crimes committed in Bucha and other Ukrainian towns for which Russia is responsible."
Moscow has said images of executed civilians are fake products of Ukrainian and Western propaganda aimed at discrediting Russia. It denies targeting civilians.
Spain, Italy, Sweden and Denmark announced similar expulsions earlier on Tuesday, and several other countries in previous days.