BANGKOK — As thousands of demonstrators marked the anniversary of a 2006 coup in the Thai capital Saturday, a rival group of protesters clashed with police and villagers near the Cambodian border, showing the country’s long-running political crisis is far from settled.

The country now appears locked in an endless cycle of protest and counter-protest by supporters and opponents of former Prime Minister Thaksin Shinawatra, who was ousted in the Sept. 19, 2006, coup on accusations of corruption, abuse of power and disrespect for the constitutional monarch.