Serbia's state news agency Tanjug reported Thursday that she was granted citizenship "because it could be in the interest of Serbia." A government decree confirming she was granted citizenship was published in June in Serbia's official gazette. Serbian officials did not comment on the reason behind the decision.
Thai foreign ministry spokeswoman Busadee Santipitaks said Friday she was unable to comment on the report from Serbia, and that the Serbian foreign ministry had not contacted its Thai counterpart. She also declined to comment on any efforts to extradite Yingluck.
Yingluck fled Thailand in 2017 just days before she was convicted of negligence for implementing a revenue-draining rice subsidy scheme while she was prime minister. She was sentenced to five years' imprisonment for in the case, which she and her supporters say was politically motivated.
Yingluck had been forced from office by a controversial 2014 court decision, and the government she had formed was toppled by a military coup shortly afterward.
Yingluck's conviction was a chapter in a long-running power struggle between Thailand's traditional ruling class and the powerful political machine founded by her brother Thaksin Shinawatra, a telecommunications tycoon.
Thaksin was prime minister in 2001-2006. He was ousted in a military coup amid accusations of corruption and likewise was sentenced to prison by a Thai court, on a conflict of interest charge he insists was politically motivated.
He fled abroad, maintaining residences in England and Dubai, and carries a passport from Montenegro, another Balkan nation, obtained in exchange for investing there. He is also reported to hold a passport from Nicaragua.
About a month after Yingluck fled, Thailand canceled her personal and official passports. She was believed to have fled through Cambodia, and since then has apparently been traveling freely.
There were reports in January this year that she holds a Cambodian passport, but Cambodian officials denied them. Cambodia's Prime Minister Hun Sen enjoys good relations with her brother Thaksin, whom he at one point appointed as an economic adviser.
Thai police once said they were seeking an Interpol arrest warrant for Yingluck, but none is known to have been issued by the international police organization. Issuing such a warrant would be controversial because of the perception that the case against Yingluck is political in nature, which would not be allowed under Interpol's rules.
Thai officials have from time to time announced efforts to extradite Yingluck and her brother from various countries, but it is not clear if they ever proceeded formally.