Image copyright Getty Images Image caption Dennis Gogel was one of three ex-soldiers arrested in a DEA sting in September 2013

A German former army sniper has been sentenced to 20 years in jail for his role in a conspiracy to kill a US federal agent.

Dennis Gogel, 29, was arrested in 2013 in a sting operation by the US Drug Enforcement Administration (DEA).

He and two others were held over an alleged plot to kill the agent and an alleged DEA informant in Liberia in exchange for $700,000 (£460,000).

They were accused of planning the act on behalf of a drugs cartel.

A US official described them as an "international band of mercenary marksmen".

US District Judge Laura Taylor Swain, who delivered the sentence on Thursday, said a lengthy prison term was necessary to deter other former soldiers from committing similar crimes.

Guilty plea

The judge said she believed Gogel was genuinely remorseful, but did not buy Gogel's claim that he was unaware that killings might be required in his role protecting a drug syndicate.

Gogel left the German army in 2010 and apologised for his actions in court.

He pleaded guilty in January to a slew of crimes, including conspiring to murder a federal law enforcement agent and conspiring to import cocaine into the US.

Two former US soldiers were arrested along with Gogel. One of them, Joseph Hunter, is alleged to have been at the centre of the group and is due to be sentenced in October.

Two further suspects were arrested in Estonia.