People living near a planned refinery for rare earth elements in Malaysia have staged a protest to try to halt its construction.
The protesters in Kuantan, eastern Malaysia, say there is a risk of dangerous radiation from the plant.
The refinery will process precious metals used in the production of mobile phones and flat-screen TVs.
Regulators insist that the plant will pose no health risk to people living in the area.
However, the BBC's Jennifer Pak in eastern Pahang state says few people believe the Malaysian government could handle a radioactive disaster.
The protest - dubbed Green Gathering 2.0 - began in a carnival atmosphere with people dressed in green and beating drums, local media reported. More than 2,000 people were reported to be taking part.
Last month shares in the Australian mining company Lynas surged after Malaysian authorities granted it a licence to operate the refinery.
Once it is completed, the plant is expected to be one of the biggest sources of rare earth elements outside China.
China is currently the biggest producer, with more than 95% share of the global market.
Global demand for rare earth metals has tripled over the past decade.
However, China has imposed a production cap and said it will cut exports of the materials, prompting accusations that it is trying to manipulate prices.