TAIPEI - Tens of thousands of protesters broke through a police cordon to block one of the busiest streets in Taiwan's capital on Sunday as they called for a new nuclear power station to be scrapped.
Chanting crowds gathered in the square outside the presidential palace where protesters had already been staging a sit-in which started on Saturday and lasted through the night.
Shouting "Stop construction of a fourth nuclear power plant!", demonstrators marched to nearby Chung-shiao West Road - an eight-lane artery where the main railway station is located - and swarmed through police lines to occupy the street, bringing traffic to a halt.
Around half an hour later, the outnumbered riot police, who had offered no resistance, retreated from the middle of the road to wild applause and cheers from the crowd, an AFP reporter on the scene said.
Buses and other vehicles were forced to detour around the intersection and traffic became paralysed.
Police put protester numbers at around 28,500.
The demonstrators pledged to continue their sit-in until Tuesday, when parliament meets to discuss the controversial nuclear power plant.
"If Taipei citizens complain about the traffic tomorrow, they should blame President Ma Ying-jeou," a activist said through a loudspeaker as she stood on top of a van.
Known as "Nuke Four" the plant outside Taipei has been one of the most contentious projects in Taiwan. Intense political wrangling has repeatedly delayed its construction, which began in 1999 and has already cost around NTD$300 billion.
Concerns about Taiwan's nuclear plants have been mounting since 2011, when Japan's Fukushima nuclear plant was hit by a tsunami which knocked out power to its cooling systems and sent reactors into meltdown.
Like Japan, Taiwan is regularly hit by earthquakes. In September 1999 a 7.6-magnitude quake killed around 2,400 people in the island's deadliest natural disaster in recent history.
Taiwan's three existing nuclear power plants supply about 20 per cent of the nation's electricity and the first reactor at the fourth power station is almost complete.
The main opposition Democratic Progressive Party opposes the facility on safety grounds, while the ruling Kuomintang party says the island will run short of power unless it goes ahead.
Respected former opposition leader and devoted anti-nuclear campaigner, Mr Lin Yi-hsiung, brought the issue into the spotlight once more on Tuesday when he started an indefinite hunger strike against the new power plant.
The 72-year-old activist said he had been forced into making the drastic move because the authorities had ignored majority public opinion against the power station.
Mr Ma on Friday promised to let the public decide the fate of the facility in a referendum, but gave no timetable for the vote.