By Erik Kirschbaum

BERLIN (Reuters) - German authorities have arrested two Russians suspected of espionage since the closing days of the Cold War, according to a report to be published in Der Spiegel news magazine on Monday.

Germany's Federal Prosecutor confirmed that two people suspected of espionage activities for a foreign country had been arrested on Tuesday in the states of Baden-Wuerttemberg and Hesse by Germany's elite GSG-9 special operations commando.

The prosecutor's office, based in the southwestern town of Karlsruhe, did not identify the suspects as Russian spies.

"The accused are suspected of having worked in Germany over a long period of time for a foreign intelligence agency," the federal prosecutor said in a statement. "The Federal Crime Office (BKA) is investigating."

Der Spiegel magazine reported that the GSG-9 commandos arrested a Russian couple, who were identified as Heidrun A. and Andreas A.. It said authorities believe the two have worked for Russia's intelligence agency since 1988.

The report, in an advance released on Saturday, said the two suspects have denied the accusations.

West and East Germany were hotbeds of espionage during the Cold War with governments and industry on both sides of the Iron Curtain infiltrated by spies. Russian Prime Minister Vladimir Putin was a former KGB spy who was stationed in Dresden, in Communist East Germany from 1985 to 1990.

But the intensity of spying abated after the collapse of communism in Eastern Europe and German unification.

The arrests, which Der Spiegel said was the first such case since German unification in 1990, could cause tensions in relations between Germany and Russia, which have become close over the last two decades.

The magazine said that Heidrun was caught listening to a coded radio message when the commandos swooped in. They were arrested in separate locations, in the towns of Marburg and Balingen.

The authorities also confiscated Austrian passports that contained false information. The documents showed that Andreas was born in Argentina and Heidrun in Peru. But German investigations in South America determined those claims were not accurate.

Der Spiegel said that German authorities believed the two began spying on West Germany near the end of the Cold War in 1988.

Another German magazine, Focus, reported on Saturday that Andreas had been working undercover at a car parts supplier and had been gathering intelligence on the company.

In a 2010 government report, German authorities said they believed Russia and China are engaged in massive espionage activities against Germany. Their focus was in the fields of industry, science and technology.

It said they were particularly interested in obtaining information about modern drive systems as well as satellite and IT technology.

(Editing by Rosalind Russell)