RANGOON, Burma — Burma’s military government broke up a peaceful protest march for a second straight day yesterday, beating and arresting participants in an attempt to tame street rallies led by democracy activists against fuel price increases.

Plainclothes officers and some civilian supporters of the junta stopped about 40 people marching quietly two miles toward their party headquarters in the capital. Authorities ordered bystanders, especially journalists, out of the area after a 30-minute standoff.

Protesters sat on the pavement and formed a human chain, but about a dozen were dragged and shoved into trucks and buses, where some were slapped around, said witnesses, who asked not to be identified for fear of being called in by police. Reporters were also roughed up by security personnel, who shouted abusive language.

Burma’s ruling junta, which has received widespread international criticism for violating the rights of its citizens, tolerates little public dissent, sometimes sentencing activists to long jail terms for violating broadly defined security laws. The protest march was the third this week against the government’s doubling of fuel prices last week in the impoverished country. Government supporters with sticks attacked some of the 300 protesters who marched Wednesday. A similar protest was held Sunday. Most demonstrators yesterday were from the party of opposition leader Aung San Suu Kyi, a Nobel peace laureate who has been under house arrest 11 years. “The authorities have arrested, tortured, beaten up, and endangered the lives of those who are peacefully expressing their dissatisfaction,” Ms. Suu Kyi’s National League for Democracy said in a statement.