Romania is demanding that the United States hand over a US marine who left the country after being involved in a car crash that killed a top rock star.
Peter: Popular performer since 1977
Police say a breath test suggests the marine had been drinking when his car hit a taxi carrying Teo Peter, 50, bass player with Romanian group Compact.
The US ambassador expressed regret but said the US authorities would first conduct their own investigation.
Romanians have reacted with shock and grief to the veteran rocker's death.
The marine, who has not been named, worked as a guard at the US embassy in Bucharest.
Police say he was driving a car that failed to stop at a junction in the capital. He hit a taxi, killed Peter and injuring the taxi driver.
Romania's foreign ministry has expressed "consternation" that the marine left the country immediately after the incident.
It sent an official protest to the US embassy, asking for the man to be brought back and to have his diplomatic immunity lifted.
In a statement, the US embassy said the US Marine Corps was co-operating fully with Romanian police.
It said the marine "was escorted out of country by an embassy security officer and is currently at a US military facility...
"The information provided by police will be used to determine, what, if any charges are brought against the individual."
Teo Peter's death has provoked an outpouring of emotion in Romania. Radio stations in his native Transylvania have been playing his music in tribute.
"Peter was very well-known, very talented and very popular," said Aura Neag from the BBC's Romanian Service who once interviewed the musician.
"He was so nice, making jokes to me," she said.