A married couple convicted of spying for Russia for 20 years have been sentenced to prison in Germany.

The BBC reported Tuesday that the couple, codenamed Andreas and Heidrun Anschlag, arrived in Germany between 1988 and 1990 posing as Austrian citizens of South American origin.

Andreas received six years and six months imprisonment, while his wife was sentenced to five years and six months behind bars.

German authorities believe the couple's names, which appeared in their Austrian passports, were false, and that they are Russians in their mid-50s.

Their daughter, born and raised in Germany, knew nothing about their spying and was unaware of their true identities.

The couple, arrested at their home in Marburg, Germany in October 2011, acted as a conduit for a Dutch Foreign Ministry official with access to NATO secrets who received a 12-year sentence.