pbr Thai Security forces have ended their offensive at a sprawling protest encampment in the centre of Bangkok and the situation is under control, the army spokesman said.br ppbr "The general situation is under control," Sansern Kaewkamnerd said in a televised address. "Security forces have ended their offensive."br ppbr This came as four senior Thai anti-government protest leaders surrendered to police after troops stormed their encampment, sparking clashes that killed at least four people, as violence rocked other areas of the city.br ppbr Using armoured vehicles and firing semi-automatic weapons from an overpass, soldiers made an early morning advance on an area occupied for more than six weeks by thousands of "red shirt" demonstrators in Bangkok's commercial heart.br ppbr As they moved close to the main protest site, top protest leaders offered to surrender on the main stage as supporters urged them to fight on, many screaming and crying as gunfire rang out nearby.br ppbr Moments later, live television showed the four in police custody, urging supporters to go home.