The Bild newspaper reported on Thursday that experts with the Federal Criminal Police Office believe in the event of a US military action against Iran, the Iranians would attack US military airfields in order to disrupt supply and logistics operations.
Federal prosecutors have launched an espionage investigation against a German businessman possibly connected to the plot who they believe has maintained conspirational contact with the Iranian embassy in Berlin, Bild reported.
However, a prosecution spokesman said later on Thursday that no evidence of a plot had been found.
"There is the beginning of a suspicion of an espionage activity for the purposes of sabotage. There were investigations which failed to support this suspicion," the spokesman said.
And the head of the Federal Criminal Police Office, Jörg Ziercke, stressed: "We do not see any immediate danger right now."
A US European Command spokesman said all threats to American interests on German soil were taken "very seriously".
"Commanders at every installation ... have the option to increase force protection measures based on their local security environment. We do not discuss specific security measures or any specific threats," he added.
There are approximately 55,000 US military personnel in Germany, not including their family members or civilian employees.
The report comes as tensions between Iran and the West have ratcheted up dramatically in recent days. A report on November 8 by the United Nation's International Atomic Energy Agency charged that Iran was likely trying to covertly develop its nuclear weapons program.
And on Wednesday Berlin temporarily recalled its ambassador to Tehran following the storming of the British embassy there by hard-line protestors.
Western diplomats have said that Iranian authorities could have prevented the overrunning of the embassy but failed to do so.
A series of mysterious explosions has also recently bedevilled Iran's weapons facilities, although they have all been attributed to accidents.