A German court sentenced an 83-year-old man to 11 years behind bars Tuesday for the attempted mass murder of a group of Jehovah's Witnesses in July.

Armed with a machine gun, knife and samurai sword, the masked pensioner stormed into a meeting of the Jehovah's Witnesses intending to kill as many of the congregation as possible, the court in Bielefeld, central Germany, said.

His weapon jammed, allowing some of the worshippers to overpower him and force him to the ground until police showed up to arrest him.

According to prosecutors, the man wanted to take revenge on the Jehovah's Witnesses whom he blamed for an decades-long estrangement between himself and his daughter, who had joined the group.

He was found guilty of 39 counts of attempted murder, the number of bullets he was carrying with him.