Vietnamese police today detained at least 15 anti-China protesters who defied a government order to stop an unprecedented series of weekly gatherings over maritime tensions. Reports said just minutes after the protest began burly plainclothes agents moved in to force the demonstrators onto a bus which had been on standby and drove them away. Other protesters, some still shouting, were then shoved onto a second bus. The demonstrations, the 11th since early June, have been held to protest against Chinese actions in the tense South China Sea, where the two nations have a longstanding territorial dispute.