A failed asylum seeker has been jailed by a German court for eight-and-a-half years for stabbing his 15-year-old ex-girlfriend to death after she broke up with him.

The defendant, identified only as Abdul Mobin D due to German privacy laws, received a jail term by a juvenile court in the western town of Landau today.

The verdict came a week after violent anti-immigrant protests erupted in the eastern city of Chemnitz over the fatal stabbing of a German national, allegedly by a Syrian and an Iraqi.

Abdul Mobin D admitted in court to stabbing the girl, identified only as Mia V, at a drugstore in the town of Kandel on December 27 last year.

Afghan asylum seeker Abdul Mobin D (right) who claimed to be 15 years old, was jailed for eight-and-a-half years for stabbing his ex-girlfriend, Mia V, 15 (left) to death

The chemist in Kandel, south west Germany, were Mia V was stabed to death just weeks after she broke up with her 'mean and jealous' boyfriend Abdul D

The attacker was overpowered by witnesses who restrained him until police officers arrived.

Prosecutors believe Abdul Mobin D, who claimed to be from Afghanistan, acted out of jealousy after the girl broke up with him.

Besides his nationality, doubts were raised about his age, which he said was 15 at the time of the crime.

An expert estimated his age the be between 17 and a half and 20 but, given the uncertainty, the proceedings were held behind closed doors and under juvenile penal rules.

Mia V was stalked and threatened by her ex-boyfriend in the weeks before she was stabbed to death

The case has been seized upon by the far-right in its campaign against migrants and comes as German police reveal that migrant murder suspects rose by a third last year.

Abdul Mobin D arrived in the German state of Hesse in April 2016 as an unaccompanied refugee, telling the authorities he was 15 years old.

His request for asylum was rejected in February 2017 but he was not immediately deported.

Abdul Mobin D and Mia V had reportedly had a relationship which lasted several months, but she broke up with him early December after he became 'jealous and mean'.

The victim's father David V said he and his family initially welcomed Abdul Mobin D 'like a son' as 'otherwise he would have had nobody', but adds that he always doubted his age.

'He is never in a million years 15-years-old. We hope that through the procedure [age test] that we will now know his true age.'

Following the end of the relationship, Abdul Mobin D reportedly stalked and threatened Mia V which saw her parents file a complaint, accusing the Afghan national of insults, threats and coercion.

Far-right protesters in Chemnitz in ex-communist eastern Germany after the alleged fatal stabbing of a German man by two immigrants from Iraq and Syria

The murders of Mia V and Daniel Hillig have been seized upon by the far-right in its campaign against migrants

Police officers notified the asylum seeker of proceedings over the harassment in person on the morning of the fatal stabbing.

Despite the doubts over his age, German doctors have resisted calls for medical testing to determine young migrants age, saying it is unethical.

The case is one in a string of high-profile crimes allegedly committed by asylum seekers that have stoked popular anger against the new arrivals and put pressure on Chancellor Angela Merkel over her liberal refugee policy, which has seen more than 1 million migrants enter the country since 2015.

Far-right party Alternative for Germany (AfD) has been mobilising regular demonstrations over the killing in the small town with a population of just 9,000, as it has sought to bolster its anti-migrant campaign.

At the peak of the protests, thousands also marched in Kandel, but the rallies have since lost momentum.

On Saturday, a demonstration in the town attracted 350 people, local police said.

Residents of the small town frustrated by the far-right rallies also lined the demonstration route, carrying banners saying 'Stop hate and incitement' or 'Kandel is colourful, not brown' - in reference to the Nazi's khaki uniforms.

Thousands of anti-migration protesters converged on the once thriving industrial city of Chemnitz after carpenter Daniel Hillig was allegedly stabbed to death by two immigrants

Riot police chased black-clad anti-fascist protesters who tried to make their way toward the far-right crowd as they waved the German flag, sang the national anthem and shouted, 'Merkel must go!'

Rhineland-Palatinate state premier Malu Dreyer accused the far-right of exploiting the teenager's death for political gains, saying this was 'intolerable'.

She said: 'It is the hope of all of us that once the trial is over, peace will return to Kandel.'

Across the country in Chemnitz, in the formerly communist eastern side of Germany, tensions have been running high over another stabbing case.

Thousands expected to attend punk concert against far-right rallies Thousands of protesters are expected to attend a concert in the German city of Chemnitz against the far-right rallies. Tonight's performances, by some of Germany's most popular bands, come as a reaction to a week of sometimes violent rallies by far-right groups protesting against migrants. The protests were triggered by the fatal stabbing of a 35-year-old German man in the eastern city on August 26, allegedly by two migrants from Iraq and Syria. The tension built up over the past week reflects the growing popularisation over Germany's ongoing effort to come to terms with an influx of more than 1 million refugees and migrants to the country since 2015. The concert is being promoted under the #WeAreMore hashtag. Advertisement

Thousands of anti-migration protesters converged on the once thriving industrial city after carpenter Daniel Hillig, 35, was allegedly stabbed to death by two immigrants.

Rival rallies in the eastern city on Saturday drew 11,000, with far-right demonstrators outnumbering counter-protesters by 8,000 to 3,000, police said.

Riot police chased black-clad anti-fascist protesters who tried to make their way toward the far-right crowd, whose members from the AfD and PEGIDA waved the German flag, sang the national anthem and shouted, 'Merkel must go!'

Eighteen people were reported injured, police said, with a Social Democrat MP also saying that his team was 'attacked by Nazis' as they were heading towards their bus.

Resentment against the arrival of more than a million asylum seekers since 2015 is particularly strong in Saxony state, where Chemnitz is located.

The AfD, railing against asylum seekers, has won strong support in the state, and surveys suggest that it is poised to become Saxony's second biggest party in next year's regional elections.

On Sunday, Foreign Minister Heiko Maas urged Germans to 'get off our sofas and open our mouths' against xenophobia.

He told Bild am Sonntag: 'All of us have to show the world that we democrats are the majority and the racists are the minority.

'The silent majority must get louder.'

Left-leaning and anti-fascist punk bands were expected to attract thousands for a free concert in Chemnitz to protest the racist violence there, held under the motto 'there are more of us'.