Thai armoured vehicles began smashing down the anti-government protesters' main barricade near the business district in Bangkok on Wednesday.

An AFP photographer witnessed the military action against the "Red Shirt" rally site blockade after security forces advanced on the sprawling camp, in what a national senator said would be a "decisive" crackdown.

Thousands of protesters, including women and children, are still holed up in the camp in the retail heart of the Thai capital.

- AFP