Russian Foreign Minister Sergei Lavrov has told his Austrian counterpart that Russia was unfairly being accused of espionage after Vienna said it was probing a former Austrian colonel for allegedly spying for Moscow for decades.

According to a statement by the Russian Foreign Ministry, Lavrov spoke of “unsubstantiated accusations” while speaking by phone on November 10 with Austrian Foreign Minister Karin Kneissl.

Lavrov said Vienna should have discussed the allegations privately and directly with Moscow and not aired them publicly.

The spy dispute risks damaging ties with one of Russia's few European allies. It is the latest in a string of cases where Moscow has been accused of espionage in EU states and elsewhere.

On November 9, Austrian Chancellor Sebastian Kurz and Defense Minister Mario Kunasek revealed that an Austrian colonel who retired five years ago is suspected of having worked for Russian intelligence from the 1990s until this year.

"Espionage is unacceptable, and Russian espionage in Europe is also unacceptable," said the chancellor.

Kneissl reacted to the scandal by cancelling an upcoming trip to Russia.

"Should the suspicions be confirmed, it would seriously strain the bilateral relations between Austria and Russia," she said.

According to the Russian Foreign Ministry, Kneissl told Lavrov during their phone call on November 10 that she hoped the affair would not damage bilateral ties.

Kneissl raised eyebrows in August when she waltzed with Russian President Vladimir Putin and bowed to him at her wedding.

According to reports, Vienna suspects a 70-year-old army official of working with Russian intelligence for several decades and is investigating him for allegedly revealing state secrets.

An Austrian Defense Ministry spokesman told the Kurier newspaper on November 10 that the information allegedly passed on by the suspect "ranged from unimportant things to more sensitive information."

However, other media reports suggested that the colonel wasn't in a position to reveal the highest levels of classified data.

The Salzburger Nachrichten newspaper reported that he is alleged to have passed on information from NATO seminars and courses he had attended, as well as information available on the army's intranet system.

Austria is not a member of NATO but cooperates closely with the Western military alliance.

With reporting by AFP and dpa