German police have arrested two suspected members of an al-Qaeda offshoot - with one accused of war crimes involving the murder of dozens of civilians.

Abdalfatah HA is accused of killing 36 employees of the Syrian government together with his Nusra Front unit in March 2013, prosecutors said in a statement.

The 35-year-old asylum seeker carried out so-called Shariah death sentences, the statement said.

German police (file picture) have arrested two suspected members of an al-Qaeda offshoot - with one accused of war crimes involving the murder of dozens of civilians

Abdulrahman AA, 26, belonged to the same combat unit as Abdalfatah HA and both participated in an armed battle against Syrian government troops, including taking over a big arms depot near Mahin in November 2013, it added.

The men were arrested in the cities of Dusseldorf and Giessen and their apartments were raided.

The men were detained by police from the western states of Baden-Wuerttemberg and North Rhine-Westphalia who also searched their apartments.

Separately, the southern state of Bavaria announced the arrest of a 33-year-old Bosnian who is believed to have supplied the Sunni militia Junud al-Sham with several vehicles.

Abdulrahman AA, 26, belonged to the same combat unit as Abdalfatah HA and both participated in an armed battle against Syrian government troops, including taking over a big arms depot near Mahin, south of Homs (pictured) in November 2013, prosecutors say

German federal prosecutors have launched around a dozen investigations concerning alleged war crimes committed in Syria or Iraq, alongside dozens of cases of suspected membership of jihadist groups.

The investigations have gained momentum following the arrival of over a million asylum seekers since 2015, including hundreds of thousands of people from Syria and Iraq.

Last July, in the first such conviction in Germany, a German jihadist was sentenced to two years in prison on war crimes charges after posing for pictures in Syria with the severed and impaled heads of two government troops.