Supporters of exiled former premier Thaksin Shinawatra gather during a rally at the Royal Plaza in Bangkok September 19, 2009. Thailand's government enacted a tough security law on Tuesday September 15, giving the military broad powers to control the planned rally on the third anniversary of the coup that led to Thaksin's ouster.[Agencies]

Thai nationalists clashed with police and villagers Saturday as they tried to march on an ancient temple on the Cambodian border, while anti-government protesters in the capital marked the third anniversary of a coup that continues to create political turmoil.

Hospitals said 15 people were injured, none seriously, in northeastern Sisaket province after members of the People's Alliance for Democracy tried to march to the gates of the temple near land claimed by both Thailand and Cambodia, demanding the Thai government seize the disputed territory.

The alliance led demonstrations that culminated in a September 19, 2006, military coup that ousted Prime Minister Thaksin Shinawatra on accusations of corruption, abuse of power and disrespect for the constitutional monarch, King Bhumibol Adulaydej.

Supporters of Thaksin rallied in Bangkok to mark the coup's anniversary, with more than 6,000 police on hand to prevent a repeat of rioting that killed at least two and injured hundreds in the last major anti-government protests in April.

Saturday's protesters want Prime Minister Abhisit Vejjajiva to step down, claiming he came to power illegitimately with the help of the military and the judiciary, two pillars of the Thai ruling class. Abhisit took power late last year after Thaksin's allies were forced out of office by court rulings of conflict of interest and electoral fraud.

Thaksin's supporters, many from poor rural areas that benefited from his generous social welfare programs, say the coup three years ago was a major blow to Thailand's democracy and was engineered by the country's traditional Bangkok-centered elite.

"We are here to show that we want democracy. This government didn't come from democracy. They're a dictatorship in disguise," said 62-year-old Jiraporn Litmontri from northeastern Loei province.

Saturday's rally was expected to reach its height in the evening. Police said 20,000 to 30,000 people were expected, and 15,000 had arrived before a heavy afternoon rain.