Opposition
About 200 people were reported to have gathered to watch the standoff between the protesters and the security forces.
The march was led by Su Su Nway, a labour activist sent to prison in October 2005 for more than seven months after reporting cases of forced labour to the United Nations.
Some witnesses said she was among those hauled off by security forces, but others said she had managed to slip away.
Su Su Nway is a member of the opposition National League for Democracy (NLD), but party officials did not immediately have details on the arrests.
The protest was the latest in a series of demonstrations against the military, which for 45 years has ruled Myanmar.
The government sparked public anger when it hiked fuel prices by as much as five-fold on August 15.
Spreading
Protests against fuel prices spread to the northwest city of Sittwe on Tuesday, where 300 people, including Buddhist monks, staged a march, Reuters news service said.
A local source in Sittwe said the march, which for the first time included monks, lasted at least an hour down a road in the centre of the city.
For the last 10 days, pro-democracy supporters across the country have defied official threats and a clampdown on dissent to stage small rallies against the fuel price increase.
State media said 56 people had been arrested over last week's protests, but Thailand-based political dissidents on Monday said it was at least 100.
Among those held last week was Min Ko Naing, who is considered Myanmar's most prominent pro-democracy advocate after detained opposition leader and Nobel peace laureate Aung San Suu Kyi.