Taiwanese MPs exchanged punches and threw water at each other before an expected vote approving a referendum on whether to go ahead with a fourth power plant on the densely populated island of 23 million people.
The fracas pitted the pro-referendum forces of President Ma Ying-jeou's ruling Nationalist Party against strongly anti-nuclear forces affiliated with the main opposition Democratic Progressive Party.
DPP MPs occupied the legislative podium amid vows to disrupt the referendum vote, tentatively scheduled for today. With a large Nationalist majority in the 113-seat legislature, the referendum Bill is expected to pass easily.
The fisticuffs broke out early in the legislative session. Associated Press television footage shows eight people pushing and shoving in one scrum. Two people scuffled on the floor, while others tried to separate them.
More than a dozen activists in bright yellow shirts chanted and waved signs on a nearby balcony, and several of them splashed water on to MPs below. A few water bottles were thrown into the fray.
The DPP has long opposed nuclear power generation in Taiwan on safety grounds, particularly given the high incidence of earthquakes on the island. Those concerns became pronounced in the wake of the Fukushima nuclear disaster in Japan in 2011.
While frequent earthquakes have led many Taiwanese to conclude that nuclear power generation constitutes an unacceptable safety risk, economic analyses suggest disruptive power shortages are inevitable if the fourth plant is not completed.
Construction of Taiwan's fourth nuclear power plant began in 1997 but was halted while the DPP was in power between 2000 and 2008. If the referendum is passed it could become operational by 2016.
Some DPP MPs object to the idea of any nuclear referendum at all, while others say that the language in the Bill needs to be changed because it is prejudicial. According to the Bill under discussion, referendum voters would be asked to vote on whether they agree with the proposition that "the construction of the fourth nuclear power plant should be halted and that it not become operational".
Taiwan began transitioning away from a one-party martial law regime in 1987 and is regarded today as one of Asia's most vibrant democracies.
But its political process has been undermined by occasional outbursts of violence in the legislature, much of which appears to be deliberately designed to score points among hardline supporters on either side of the island's long-standing political divide.