By Mari Saito and Maria Tsvetkova

BERLIN (Reuters) -The European Union on Tuesday announced sanctions against three pro-Russia activists whose activities promoting the Kremlin's agenda inside Germany were first revealed in a Reuters investigation in 2023.

Since Russia's full-scale invasion of Ukraine in 2022, Elena Kolbasnikova and her husband Max Schlund have been organising pro-Kremlin rallies in Germany to urge Berlin to abandon its military support for Kyiv.

In the sanctions listing, the EU said both Kolbasnikova and Schlund, who also goes by the name of Rostislav Teslyuk, had taken part in "destabilising activities".

It said Kolbasnikova had promoted "violent acts" committed by her husband including organising car rallies to "intimidate Ukrainian minors" who were seeking refuge in Germany.

The listing said the couple had close ties with, and were financially supported by, Rossotrudnichestvo, a Russian government cultural promotion agency.

The sanctions mean any assets the three targeted activists - including a Russian associate of Kolbasnikova and Schlund - have inside the EU will be frozen, and they will be barred from entering any of the bloc's member countries.

On a public Telegram group run by both Kolbasnikova and Schlund, the pair denounced the sanctions. "PEOPLE WHO FIGHT FOR PEACE ARE BEING SUBJECT TO SANCTIONS," they wrote. "IDIOCY."

When reached by phone for comment on Tuesday, Schlund told the Reuters reporter to "fuck off" before hanging up.

Reuters first reported on the couple in 2023, detailing how they were at the centre of an effort in Germany to turn public opinion against the German government's continued support for Ukraine.

In its report, Reuters revealed how the couple had received plane tickets from a Russian cultural promotion body that is part of Rossotrudnitschestwo to travel to a forum for civil society activists in Moscow that was co-organised by the Russian government.

Kolbasnikova and Schlund left Germany last year after they said authorities there had barred them from re-entering the country.

The sanctions listing on Tuesday said a criminal investigation against the pair over their alleged support for pro-Russian separatists in Ukraine's Donbas region was ongoing.

Reuters in 2023 also reported that the couple had donated funds to a Russian army division fighting in Ukraine, and that it had used the money to purchase walkie-talkie radios, headphones and telephones.

In the same listing, Europe also imposed sanctions on Andrei Kharkovsky, a Russian citizen residing in Germany who is a member of a Cossack organisation endorsed by the Kremlin.

In the 2023 report, Reuters wrote that Kharkovsky provided security for Kolbasnikova and Schlund at pro-Moscow rallies they held in Germany.

The listing said the group Kharkovsky was part of, the Union of Cossack Warriors of Russia and Abroad, was linked to the Kremlin and accused it of supporting pro-Russian separatists.

Reuters was not immediately able to reach Kharkovsky for comment.

(Additional reporting by Anton Zverev; editing by Mark Heinrich)