Thailand's Senate elections have been marred by violence in the insurgency-plagued far South as suspected insurgents ambushed police and election officials in five separate attacks, killing three people and injuring at least 18 others.
The latest violence occurred when a roadside bomb exploded and hit a car carrying ballot boxes for Senate votes in Narathiwat province in the afternoon, killing an election worker and injuring nine people.
Earlier Wednesday, a policeman guarding a poll station in Narathiwat was killed and another injured by unidentified gunmen who were pretending to be voters while entering the poll station.
In a morning attack, a group of suspected insurgents fired on a group of police officers and election officials in the same southern border province, killing one policeman and injuring seven persons.
Meanwhile, another two separate attacks plagued the nearby Yala Province, causing several persons wounded.
Polls closed at 3 p.m. local time (0800 GMT) around the country and results of the new 200-seat Senate will be available on Thursday.
There was no report of any untoward incident in other regions but vote buying was reported across the country, including Bangkok, the Thai News Agency said.
The People's Network for Elections (P-Net), a Bangkok-based election watchdog, said it received a number of complaints over election fraud and vote buying from around the country.
"Complaints over vote-buying in other provinces came in from Samut Songkhram, Udon Thani and Sakon Nakhon, but the worst is the northeastern province of Sri Sa Ket where at least Bt100 million ( 2.5 million U.S. dollars) was spent in such illicit acts," said Varin Thiemjarat, P-Net secretary-general.
Under the Constitution of 1997, Wednesday's election is only the second time that Thais have voted for Senators. Previously members of the Upper House had been appointed by the government.
There are 1,477 candidates vying for the 200 seats in the Upper House, but the Election Commission disqualified 14 of them.
The duties of the Upper House include examining all draft laws and to select members of the independent agencies which are constitutionally intended to act as check and balance mechanisms to scrutinize the government.
The string of attacks on Wednesday took place just one day after the Cabinet agreed to extend the enforcement of the government's Emergency Decree for another three months in the predominantly-Muslim provinces of Yala, Pattani and Narathiwat where more than 1,200 people have been killed since violence erupted in early 2004.