YANGON, Aug 23 (Reuters) - A gang of supporters of Myanmar's military rulers halted a small protest march on Thursday against dramatic fuel price rises in Yangon and tried to force 30 people onto trucks to take them away. A tense stand-off ensued as the protesters, who had been walking towards the headquarters of the opposition National League for Democracy (NLD), refused to get into the trucks. A Reuters reporter was prevented from taking photographs. On Wednesday, the junta arrested 13 top dissidents and deployed armed police and gangs of spade-wielding supporters on the streets of Yangon to squash protests against soaring fuel prices and falling living standards.