Meanwhile, reports suggest that the authorities are bolstering their military presence, stationing vehicles and troops out of sight in local compounds.

In the latest demonstrations - the most sustained campaign for several years - about 40 members of the opposition National League for Democracy (NLD) - whose co-founder Aung San Suu Kyi is under house arrest in Yangon - marched without placards through the streets of the capital.

They walked for about two miles towards their party’s offices in the east of the city before a stand-off with the security forces and pro-government gangs. They sat on the pavement and formed a human chain in an attempt to prevent the security forces from dragging them into the waiting trucks and buses.

But witnesses said that up to a dozen protesters were taken away, many of them being punched and slapped by the police as they were driven off in trucks belonging to the Union Solidarity and Development Association (USDA), an or-ganisation established by the government to use against dissidents. Reporters and bystanders were ordered out of the area, and some members of the media were also reportedly roughed up.

The demonstrations have been held specifically to protest against the government’s decision to order a massive rise in the price of compressed natural gas and diesel. The move has added to the hardships for an already beleaguered and impoverished population.

Thirteen leading dissidents were arrested in midnight raids at the beginning of the week after the first protest on Sunday. More were held after a second march on Wednesday. Mark Farmaner, of the pressure group Burma Campaign UK, said: “These reports [of a military buildup in Yangon] are very disturbing. We know from experience that the regime is quite prepared to open fire on peaceful protesters.”