Two German police officers suffered fatal gunshot wounds during a routine traffic stop on Monday morning.
The shooting happened at about 4.20am in the Kusel district of western Rhineland-Palatinate state, about 30 kilometres from the city of Kaiserslautern.
A 24-year-old female officer and her 29-year-old male colleague called for help, but died from their injuries.
"We are urgently searching for the fugitive perpetrators," regional police said in a statement.
"At least one is armed," they said, urging motorists not to pick up hitchhikers.
The police said they had no description of the wanted vehicle and did not know the direction in which the occupant or occupants had fled.
German news agency dpa, citing unidentified security sources, said that the officers reported finding dead game in the car before the shooting started. The Bild daily newspaper also reported that find, without citing sources.
Kaiserslautern city police said they had extended their search area to the neighbouring state of Saarland.
"Please do not pick up any hitchhikers in the Kusel district!" police tweeted.
Germany's GdP police union expressed its "deep shock and sadness" over the shooting.
"Our thoughts are with the relatives and loved ones of the colleagues who died as a result of an act of violence in the line of duty," GdP deputy chief Joerg Radek said.
