Three people have been arrested on suspicion of spying for Russia as part of a National Security Investigation on Wednesday.

Three people were arrested in Britain on suspicion of spying for Russia, Britain's Metropolitan Police announced Thursday. File Photo by Andy Rain/EPA UPI

Sept. 18 (UPI) -- Authorities in Britain arrested three people on suspicion of spying for Russia, the Metropolitan Police announced Thursday.

The Metropolitan police said a 46-year-old man, a 41-year-old man, and a 35-year-old woman were arrested on Wednesday in Grays, Essex and taken to a police station in London as part of an investigation into suspected National Security Act offenses.

"The country to which th eallegations relate is Russia," police said.

All three people have since been released on conditional bail after officers carried out searches at the addresses in Essex, the Met said.

The investigation is still ongoing.

"Through our recent national security casework, we're seeing an increasing number of individuals who we would describe as 'proxies' being recruited by foreign intelligence services," Commander Dominic Murphy, Head of the Counter Terroism Command said.

There are also two men who are awaiting sentencing after being recruited by the Wagner group to carry out an arson at a Ukrainian inked warehouse.

"They are facing potentially lengthy custodial sentences, although, to be clear, today's arrests are in no way connected to that investigation," he added.

The arrests on Wednesday were not connected to these two.

The Wagner Group is a private military organization that acts in favor of Russia.