Prosecutors in Frankfurt issued a statement on Friday to say the suspects were detained in police raids involving 200 officers in the Frankfurt region earlier in the day.
Commenting on the raids, Hesse state interior minister Peter Beuth said: "Police intervened in a timely manner to prevent possible attack plans at an early stage."
There were no details on the nationalities of the suspects, whose ages were given at between 20 and 42 years. They live in the Frankfurt, Offenbach, Wiesbaden and Mainz areas. Eleven people were initially arrested but the investigation was centered on ten suspects.
The main suspects were a 21-year old man from Offenbach and two 31-year-old brothers from Wiesbaden, all associated with the local Islamist Salafist community. All are German citizens.
The number of confirmed Islamists in the state of Hesse in 2017 was 4,170, including 1,650 Salafists.
According to the initial investigation, the accused were planning to use a vehicle and firearms to kill as many "unbelievers" as possible. They had rented a large vehicle, made contact with weapons dealers, and started to raise funds.
During the raids, police found and seized over €20,000 ($22,500) in cash, several knives, small quantities of narcotics, a variety of documents and electronic data storage equipment.
The charges include funding terrorism and conspiring to commit a crime. The accused are due to appear before a judge at the District Court of Frankfurt on Friday afternoon.
A number of plots have been foiled by police in recent months, with some similar raids.
jm/msh (Reuters, AFP)