Russian hackers have targeted international peace monitors in Ukraine, according to German intelligence, as the Kremlin dismisses claims that it tried to influence the US election as a "witch hunt".

Investigators have uncovered evidence that a notorious Russian hacking group believed to be linked to the Kremlin was behind an attack on computers of the Organisation for Security and Cooperation in Europe (OSCE) last month, Hans-Georg Maassen, the head of Germany’s BfV domestic intelligence service said.

He named the group responsible as APT28, another name for Fancy Bear, a group of hackers that has been implicated in the theft of emails from Democratic Party servers in the US.

German intelligence also believes the group was behind a series of cyber attacks on the German parliament in 2015.

The OSCE is responsible for monitoring the ceasefire between government forces and pro-Russian rebels in eastern Ukraine.