Dozens of pro-democracy supporters were detained Tuesday after a top labour activist tried to launch a new protest in Yangon against a sharp rise in fuel prices, witnesses said.

About 50 activists had gathered near a bus stop close to the former campus of Yangon University on the north side of Myanmar’s main city, but plainclothes police and pro-junta militia broke up the group after only 10 minutes, witnesses said.

Protesters chanted “Lower fuel prices, lower commodity prices!” as they walked along a main road.

About 200 people gathered to watch the standoff between the protesters and the security forces, witnesses said.

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. Calls to her cell phone went unanswered.

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 bold demonstrations against the military, which for 45 years has ruled impoverished Myanmar with an iron fist and kept a tight lid on dissent.

But the junta sparked public anger when the government secretly hiked key fuel prices by as much as five-fold on August 15.

That immediately doubled the cost of transport, which left many people unable to even afford the bus fare to get to work.

For the last 10 days, pro-democracy supporters 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.

Min Ko Naing was arrested along with 12 activists for leading about 500 protesters in a peaceful march in Yangon on August 19 — the biggest anti-government rally here in at least nine years.

Myanmar’s state media has said only that authorities were interrogating Min Ko Naing and the 12 others and that the junta would take legal action against them. Most of them have already spent more than a decade in prison.

The 13 were members of the pro-democracy 88 Generation Students group, which is made up of former student leaders who led an uprising against military rule in 1988.

That uprising, which initially began as a protest over Myanmar’s harsh economic conditions, ended with soldiers firing into a crowd of students, killing hundreds if not thousands.

The uprising led to the creation of the NLD, headed by Aung San Suu Kyi. The party won a landslide victory in 1990 elections, but the junta never recognised the result.