LISBON: Portuguese police have arrested a rabbi from Porto, Daniel Litvak, who certified the Sephardic descent of the Russian oligarch Roman Abramovich so that he could obtain Portuguese nationality.

Litvak’s arrest is reportedly possibly connected with an investigation into alleged irregularities in the granting of certificates for Sephardic Jews.

Abramovich was one of the beneficiaries of these certificates whose securing of Portuguese nationality aroused criticism.

The Portuguese prosecutors office reported in January that it had opened an investigation into the granting of nationality to the Russian billionaire.

Abramovich became a naturalised Portuguese citizen in April last year according to a law which recognises the descendants of Sephardic Jews who lived in the Iberian Peninsula until they were expelled at the end of the 15th century.

The Institute of Registries and Notaries of Portugal has also opened an internal investigation into this case.

Abramovich, 55, born in the former Soviet Union, currently has four nationalities: Russian, Israeli, Lithuanian and Portuguese.

The law that allows the descendants of Sephardic Jews to become Portuguese nationals was approved in 2015 and since then more than 30,000 people have resorted to it to have a Portuguese passport.