The sister of exiled Prime Minister Thaksin Shinawatra swept to victory in fractious Thailand's elections Sunday, heralding an extraordinary political turnaround five tumultuous years after her fugitive billionaire brother was toppled in an army coup.

The vote paves the way for 44-year-old Yingluck Shinawatra, who has never held office, to become this Southeast Asian kingdom's first female prime minister. A large mandate to govern could help the new government navigate a way out of out of the crisis that has plagued Thailand since Thaksin's 2006 overthrow. But the question remains whether the nation's elite power brokers, including the monarchy and the army, would accept the result.

Thaksin was barred from politics years ago after a graft conviction, and the U.S.-educated Yingluck, who he calls "my clone," is widely considered her proxy.

The incumbent premier, Abhisit Vejjajiva, conceded defeat Sunday night and said he was ready to become the opposition.

With 94 percent of the vote counted, preliminary results from the Election Commission indicated Yingluck's Pheu Thai party had a strong lead with 261 of 500 parliament seats, well over the majority needed to form a government. Abhisit's Democrats had 162 seats.

Speaking to a throng of cheering supporters at her party headquarters in Bangkok, Yingluck declined to declare victory until final results are released. But she said: "I don't want to say that Pheu Thai wins today. It's a victory of the people."