More than 2,000 anti-government protesters forced the postponement of the opening meeting of an Asian summit on Saturday, demanding the gathering be canceled unless the Thai prime minister resigns. Protesters blocked leaders from leaving their nearby hotels and marched to the meeting venue, clashing with a group of rival demonstrators. The two sides threw rocks and smoke bombs at each other about 3 kilometers from the venue. Thai Government Spokesman Panitan Wattanayagorn said two or three people were injured in the clashes and that authorities were investigating reports of shots fired and an explosion. A breakfast meeting of the foreign ministers of China, Japan and South Korea was also canceled Saturday because of the protests, the Japanese Foreign Ministry press secretary Kazuo Kodama said.