Trying to recruit a Russian intelligence officer, a CIA agent had been shortly detained in Moscow.

A CIA agent had been shortly detained in Moscow after he had been caught trying to recruit a Russian intelligence officer.

“The man, named as US diplomat Ryan Fogle, was held overnight before being released to US officials," Russia's Federal Security said.

Mr Fogle is said to have worked as third political secretary at the US embassy in Moscow, which has issued no comment on the matter so farrvice (FSB) said.

It was also reported that he was holding a large sum of money, technical devices and written instructions for the agent he had tried to recruit.

Russia has declared him "persona non grata" and ordered his expulsion, the foreign ministry said on its website.

The US ambassador to Moscow, Michael McFaul, had been summoned.