A group of Jordanian extremists was behind an alleged plot to bomb an Israeli passenger jet flying from Germany, German press reports said on Tuesday.
The plan was to pay an employee with special access to the security-restricted zone at Frankfurt airport to smuggle a case containing explosives on board an El Al jet, Der Tagesspiegel daily reported, quoting security service contacts.
The plot broke down when the suspected attackers failed to agree with the airport employee on the payment for planting the case on a plane.
The office of Germany's federal prosecutor Monika Harms revealed the alleged plot on Monday.
It said six suspects were arrested by police on Friday, although all but one were released on Saturday. The prosecutor's office gave no details of their nationality nor of their intended target.
Der Tagesspiegel said searches of the suspects' apartments had failed to find any traces of explosives.
The security services had learned of the alleged plot in the summer and immediately placed the group under surveillance.
Security services considered it unlikely that the group would have succeeded in smuggling a bomb onto an El Al plane, but agents decided to intervene as early as possible although they were worried that doing so would prevent them being able to gather enough evidence to bring charges, the report said.
They also do not believe there were direct links between the group and the alleged plot to bomb US-bound jets flying from Britain using liquid explosives taken on board in hand luggage.
British authorities have charged 11 people with conspiracy to murder and preparing an act of terrorism in relation to the suspected plot.