Germany is repatriating a Bundeswehr platoon from Lithuania after its soldiers were accused of rightwing extremism and sexual assault, in a case that has again exposed the prevalence of hard-right views in Germany’s armed forces.

The incident comes just months after the defence ministry was forced to undertake a wide-ranging reform of its elite military division, the Kommando Spezialkräfte (KSK), and disband one of its companies after some of its members were found to have rightwing sympathies.

It was also announced on Wednesday that investigators are probing a number of police officers in the western state of Hesse who belonged to an elite unit known as the Special Operations Command, or SEK, and had allegedly shared banned Nazi content in a chat group.

A spokesperson for the German defence ministry said the armoured infantry platoon stationed in Lithuania was being investigated for suspected sexual coercion, using racist and anti-Semitic insults, and “extremist behaviour”.

The platoon is part of a Nato battle group in Lithuania known as “enhanced forward presence” which is designed to improve the alliance’s deterrence capability against Russia.

The 600 soldiers stationed there for the Bundeswehr, or federal armed forces, carry out joint exercises with the Lithuanian army and are supposed to act as a “tripwire” should tensions with Moscow escalate.

“The fact that this happened in Lithuania, where we stand up for common values side by side with our Nato partners, makes such behaviour by individuals not only inexcusable but absolutely shameful for us all,” said spokesperson Christina Routsi.

The platoon will be brought back to Germany on Thursday and relieved of service, Routsi said, and procedures had begun to dismiss the main culprits. “Such behaviour has no place in the Bundeswehr,” she said.

German news magazine Der Spiegel first reported on the offences allegedly committed by the platoon’s soldiers. It is said they partied in a hotel in the central Lithuanian district of Rukla on April 30 and got so drunk and rowdy that hotel staff alerted German military police.

Spiegel said that during questioning, soldiers in the platoon revealed that on April 20, Adolf Hitler’s birthday, some of their colleagues had sung a birthday song to the dictator. They did so despite the express orders of a sergeant present at the scene, who told them to stop.

Routsi said it had also emerged that 569 rounds of ammunition had gone missing from the platoon after a shooting exercise.

She said it was unclear whether it was a “booking error” or if the ammunition had been stolen. The commander of the Bundeswehr induction command had sent a team of investigators to look into the incident.