BANGKOK (AFP) - Allies of Thailand's fugitive ex-leader Thaksin Shinawatra stormed to victory in elections Sunday, in a remarkable comeback after years of turmoil sparked by his overthrow in a military coup. Prime Minister Abhisit Vejjajiva conceded defeat and congratulated the opposition led by Thaksin's youngest sister, Yingluck Shinawatra, who is now set to become Thailand first female premier. With almost all the votes counted, Puea Thai had won a clear majority with 263 seats out of 500, well ahead of Abhisit's Democrats with 161, according to the Election Commission, which estimated turnout at 74 percent. "The outcome is clear - Puea Thai has won the election and the Democrats are defeated," Abhisit told supporters at the party's Bangkok headquarters. The United States on Sunday hailed the people of Thailand for their "robust participation" in their parliamentary elections, as allies of the Kingdom's fugitive ex-leader Thaksin Shinawatra rallied to victory. "We congratulate the people of the Kingdom of Thailand, our long-time friend and ally, for their robust participation in the July 3rd parliamentary elections," said State Department spokesperson Victoria Nuland. "The choice of who will lead Thailand now rests with those representatives elected by the Thai people," she said. The poll was the first major electoral test for the elite-backed government since mass demonstrations by Thaksin's "Red Shirt" supporters last year paralysed Bangkok and unleashed the worst political violence in decades. A smiling Yingluck earlier addressed jubilant supports at the Puea Thai Party's headquarters in the Thai capital, saying: "Thaksin has called to congratulate me and said there was a tough job ahead." The 44-year-old telegenic businesswoman, a political novice who Thaksin has described as his "clone", said she was working on building a coalition with the smaller Chart Thai Pattana and other parties. "People are giving me a chance and I will work to my best ability," she added. Amid fears that an opposition victory could unleash more deadly protests or even another army takeover, Thaksin called on all sides to respect the outcome of the ballot. "All parties must respect the people's decision otherwise our country cannot achieve peace," the former billionaire telecoms tycoon told Thai television by telephone from his base in Dubai. Toppled by the military in 2006 and now living in self-imposed exile to avoid a jail term for corruption, Thaksin nevertheless dominated the election in Thailand, where he remains a hugely divisive figure. He is adored by rural voters for his populist policies while in power such as cheap healthcare and microcredit schemes, but hated by the ruling elite who see him as corrupt, authoritarian and a threat to the revered monarchy. The election is seen as a major test of the kingdom's ability to emerge from its long political crisis, which has seen years of street protests by Thaksin's "Red Shirt" supporters and the rival "Yellow Shirt" royalists. More than 170,000 police were deployed to secure the vote, but it appeared to proceed peacefully. Long queues were seen at polling stations.