A Swedish-Russian man arrested last year in a spectacular helicopter raid on his suburban Stockholm home was charged in Sweden on Monday with providing Western technology to Russia's military intelligence.

Sergei Skvortsov, a 60-year-old dual national, was formally charged with carrying out "unlawful intelligence activities" against the United States and Sweden for a decade until his arrest in November 2022, court documents showed.

Skvortsov is suspected of procuring Western technology information and products that were off-limits to Moscow due to international sanctions, and passing them on to Russia's military industry.

He is accused of having ties to Russia's military intelligence division, the GRU.

According to the prosecution, Skvortsov had been spying on the United States since January 1, 2013 until his arrest in November 2022, and on Sweden since July 1, 2014.

In the indictment filed with Stockholm district court, prosecutor Henrik Olin accused him of gathering "information and the actual acquisition of various items that the Russian state and the defence forces could not acquire on the open market due to export rules and sanctions."

Olin accused him of "localising the items requested by the Russian state and the armed forces, negotiating and carrying out the purchase and further organising the transport of the goods while concealing the actual end user."

Sweden's charge of "unlawful intelligence activities" is a notch lower than espionage.

Skvortsov, who has been held in detention since his arrest, faces up to four years in prison if found guilty.

He has denied the allegations.

His lawyer, Ulrika Borg, told AFP she was prevented from speaking about the details of the case by a gag order.

"But what I can say is that my client stands by what he has said throughout this entire case... He denies any wrongdoing."

Borg said she expected the trial to begin within two weeks, held in part behind closed doors due to reasons of national security.

- Dawn raid -

Skvortsov and his wife were arrested in a dawn raid on their large home in the leafy Stockholm suburb of Nacka, when two Black Hawk helicopters and an elite commando task force swooped down on their house.

His wife was later released and is no longer a suspect.

The couple moved to Sweden in the 1990s and ran several import-export companies.

Among the 81 items listed as evidence in the charge sheet were computers, hard drives, USB sticks, mobile phones and documents seized from their home.

US authorities, including the US Federal Bureau of Investigation, helped Swedish authorities in their investigation of the case.

Just after the couple's arrest last year, Russia's foreign ministry said it was part of a "broader anti-Russian hysteria in the West" and said some countries had "a real spy mania".

Monday's indictment comes on the heels of another sensational spy case in Sweden.

In January, a former Swedish intelligence official of Iranian origin, Peyman Kia, was handed a life sentence for spying for Russia for a decade, and jailed his brother for 10 years.

Kia served in Sweden's intelligence service Sapo and military intelligence units.

That case is considered one of the Scandinavian country's most serious espionage affairs in history, given Kia's access to highly classified information, which he was found guilty of gathering for Russian military intelligence from 2011 to 2021.