MOSCOW (AP) — Former Georgian President Mikhail Saakashvili, who moved to Ukraine to lead one of the country's most corruption-ridden regions, says he will fight to keep his Ukrainian citizenship.

President Petro Poroshenko stripped Saakashvili of his citizenship by special decree on Wednesday after Ukrainian officials received unspecified documents from Georgia. The move was widely seen as political retribution against Saakashvili, who was getting increasingly popular.

In a video message released Thursday the former Georgian president vowed to fight the decree and accused Poroshenko of colluding with Georgian authorities.

Saakashvili was stripped of his Georgian citizenship in 2015 after being appointed governor of Ukraine's Odessa region. Georgia is seeking his extradition on charges connected with the violent dispersal of protests during his presidency and a raid on a private television station.