Election officials began investigating would-be Prime Minister Yingluck Shinawatra's campaign Wednesday, a move that may slow Thailand's transition to a new government and risks more political unrest if she is disqualified.
The probe came a day after the Election Commission said it had certified 358 winners in the 500-seat lower house of parliament, but was deferring certifying 142, including Yingluck and her main rival former Prime Minister Abhisit Vejjajiva.
Thailand has been wracked by political turmoil since Yingluck's brother, former Prime Minister Thaksin Shinawatra, was ousted in a military coup in 2006 after being accused of corruption and disrespect for the monarchy.
The complaints against Yingluck and her Pheu Thai party concern the possible involvement of Thaksin and other banned politicians in her campaign for the July 3 elections. More than 100 executives of Thaksin's party in 2007 were barred from politics for five years for election law violations.
The Election Commission's decision could mark the start of another "judicial coup" against the pro-Thaksin camp, said Pavin Chachavalpongpun of the Institute of Southeast Asian Studies in Singapore,
"This is a postelection attempt to prevent the Pheu Thai party from coming to power," Pavin told The Associated Press by telephone. At the very least, he said, "it will stir up resentment among their supporters. And it could end up prolonging the Thai crisis."
The Election Commission cited Yingluck for allowing Somchai Wongsawat, a former prime minister and Thaksin's brother-in-law, to join her election campaign activities in northern Chiang Mai province.
Yingluck put on a brave front, saying she is sure the Election Commission "will grant justice to me and the Pheu Thai party."
She described the postponement as part of a "normal process" for the commission and said it still had a month to investigate and make a final decision. More certifications are expected next week, once the commission absolves the candidates of the complaints against them.
Among those waiting to be endorsed is Abhisit, the former prime minister. No reason was given but Thai media have speculated it was over allegation of vote-buying.
Although Abhisit won a seat in Parliament, his Democrat Party lost power after finishing second in the election behind Pheu Thai party, which secured 265 seats.
It quickly formed a coalition with smaller parties for 300 seats total. The quick agreement had raised expectations a new government would take office quickly as well.
The Election Commission said that apart from Somchai, Yingluck allowed other people associated with Thaksin also barred from politics to help in her campaigning. The statement did not name them.
It said there were complaints against the Pheu Thai Party for including Thaksin in the party's election campaigns by using the slogan "Thaksin Thinks, Pheu Thai Does" in its posters. Thaksin is also barred from politics for five years.
Pheu Thai trumpeted its connections with Thaksin, the country's most popular politician, but the law is not clear on what is allowable, and party leaders claim Thaksin had no say in their activities.
Thaksin lives in exile in Dubai to escape a two-year prison term on a graft conviction that he says is politically motivated. His overthrow was followed by controversial court rulings that removed two pro-Thaksin premiers who came after him _ one of whom won a 2007 vote intended to restore democracy in the nation of 66 million people.
Many see his post-coup struggle as pitting long-marginalized rural Thais against an elite alliance comprising the army, the military and powerful businessmen and politicians.
Associated Press writers Todd Pitman and Grant Peck contributed to this report.