Three Chinese nationals have been arrested in Georgia on suspicion of attempting to illegally purchase 2kg of uranium.

Lasha Maghradze, deputy head of the nation's State Security Service (SSG), told a news briefing the group planned to pay $400,000 (£300,570) for the nuclear material in the capital, Tbilisi, before transporting it to China via Russia.

The alleged plot was unearthed by intelligence agents while one member of the group was attempting to buy the radioactive substance on the black market, he said.

The three pleaded not guilty at a court in Tbilisi and have been placed in custody to prevent them from fleeing the country, according to public broadcaster Georgia Today.

They face up to five years in prison under a provision of Georgia's criminal code banning the purchase of nuclear material.

Mr Maghradze told reporters the operation was being coordinated by other members of the group in China.

SSG footage shows armed soldiers swooping on a car and detaining three individuals.

It also shows two glass jars containing a yellow substance in a car boot, which tests identified as uranium.

It is unclear what isotope of uranium the men are alleged to have sought, though all can emit harmful radiation, and their intended purpose for it.

As a former Soviet nation, Georgia had stores of nuclear materials following the bloc's collapse in 1991.

The security of those materials has been an ongoing concern, with several serious incidents of uranium being illicitly sold in the years since.

In July, the SSG arrested two people - one Georgian and one Turkish national - for attempting to trade $3m worth of uranium.