A Russian journalist who wrote about his country's 'shadow army' in Syria has died after falling from the balcony of his fifth-floor flat.

Maksim Borodin fell from his apartment in Yekaterinburg, a major city in the Urals, on Thursday and died from his injuries in hospital on Sunday, news agencies reported.

Investigators said yesterday that they were not treating the death as suspicious, but Russia has a long history of reporters being murdered and media have called for a proper investigation.

Maksim Borodin fell from his apartment in Yekaterinburg, a major city in the Urals, on Thursday and died from his injuries in hospital on Sunday, news agencies reported

Borodin worked for the news service Noviy Den (New Day) and recently wrote on the deaths of employees of the so-called 'Wagner Group', the private army Moscow is using in Syria.

Thousands of mercenaries have reportedly been deployed to Syria by a shadowy contracting company believed to be bankrolled by Yevgeny Prigozhin.

Prigozhin was indicted by the US in February on charges that he funded the 'troll factory' alleged to have tried to influence the 2016 presidential election.

'There are no grounds for launching a case,' the local investigative committee told the TASS news agency yesterday.

'Several versions are being considered, including that this was an unfortunate accident, but there is no sign a crime has been committed,' it said.

The Investigative Committee, Russia's main investigative agency, said there was no reason to believe a crime had been committed.

But Polina Rumyantseva, the editor of Noviy Den, said there was also no reason to class the death as suicide.

In 2006, the esteemed journalist Anna Politkovskaya was murdered in Moscow

He said: 'We were able to visit the apartment of Maxim together with the police and forensic experts on Friday.

'The intermediate conclusion is that Maxim fell out of the balcony of his apartment where he probably was smoking.

She added: 'As Maxim had big plans for his personal life and career, there is nothing to support a verdict of suicide.'

Meanwhile his friend, Vyacheslav Bashkov, wrote that Borodin had called him on Wednesday morning to say his building was surrounded by masked men working for the security forces.

Russian news reports cited police as saying the apartment was locked from the inside.

The local committee told AFP it would not comment on the incident to foreign media.

But Harlem Desir, the representative for freedom of the media at the Organization for Security and Co-operation in Europe, said Borodin's death was 'of serious concern'.

'I call on the authorities for a swift and thorough investigation,' he said on Twitter Monday.

Russia has a disturbing record of attacks on reporters, with 58 killed since 1992, according to the Committee to Protect Journalists.

In 2006, esteemed journalist Anna Politkovskaya - who frequently attacked Putin and exposed Russian atrocities during the Second Chechen War - was murdered in Moscow.