UPDATE 2-Romania detains suspects in Russia-linked treason case, 101-year-old retired general's house raided

* Romania detains six over alleged attempt to overthrow the state with Russian aid * Expelled Russian diplomats accused of supporting anti-constitutional activities * Prosecutors say targeted group aimed to withdraw Romania from NATO and change national symbols (Adds quotes from intelligence agency and retired general in paragraphs 4-6, 8-9) BUCHAREST, March 6 (Reuters) - Romania detained six people on charges of trying to overthrow the state with Russia's help, prosecutors said on Thursday, and a 101-year-old former army major general said his home had been raided as part of the investigation.

* Romania detains six over alleged attempt to overthrow the state with Russian aid

* Expelled Russian diplomats accused of supporting anti-constitutional activities

* Prosecutors say targeted group aimed to withdraw Romania from NATO and change national symbols

(Adds quotes from intelligence agency and retired general in paragraphs 4-6, 8-9) BUCHAREST, March 6 (Reuters) -

Romania detained six people on charges of trying to overthrow the state with Russia's help, prosecutors said on Thursday, and a 101-year-old former army major general said his home had been raided as part of the investigation. The suspects were detained on Wednesday, the same day Romania - a European Union and NATO member state - declared the Russian embassy's military attache and his deputy personae non grata for what it said were acts contravening diplomatic rules.

Moscow has said it will respond to the move. "The members of the criminal group repeatedly contacted agents of a foreign power, located both in Romania and the Russian Federation," anti-organised crime prosecutors agency DIICOT said in a statement, which did not name the suspects.

Romania's intelligence agency SRI said the two expelled Russian diplomats "collected information in areas of strategic interest and took measures to support the anti-constitutional moves of the group". Russia's foreign ministry did not immediately respond to a request for comment.

MILITARY STRUCTURE Prosecutors said the group had a military-type structure, with judicial sources naming 101-year-old former army major general Radu Theodoru as a suspect.

Theodoru, a Holocaust denier who has repeatedly praised Romania's fascist World War Two leadership, said in a recorded interview with his daughter posted on his Facebook page that he believed the current government represented "an anti-Romanian state, a system organised to rob this country". "They wasted this country and now they defend themselves and find reasons to misinform the public," he added. Theodoru did not immediately respond to a request for comment.

Prosecutors said the group had taken steps to negotiate with external forces regarding the potential withdrawal of Romania, which shares a border with Ukraine, from the NATO military alliance. They said the group aimed to install a new government and dissolve the current constitutional order, introducing a new flag, national anthem and changing the country's name.

Political tensions have been running high in Romania since its top court voided the presidential election in December amid accusations of Russian interference - denied by Moscow - in favour of far-right frontrunner Calin Georgescu. Georgescu is himself under

investigation on six charges, all of which he denies.

The investigation announced on Thursday is unrelated to Georgescu, prosecution sources said. Judicial sources quoted by TV station Antena3 said one of the expelled Russian officials was loosely tied to a suspect in the Georgescu investigation.