Police in Sweden and Denmark are keeping a close watch but have not yet spotted either the man or his car.
The German man had been receiving medical treatment before his disappearance and a doctor informed German police that he was in poor condition. He is not suspected of committing any crime.
“The man disappeared on Monday. He is said to be carrying a weapon. We received a description of the man from Interpol and have alerted customs and all police districts with borders or ferry connections to foreign countries,” said police spokesman Anders Frantzén.