Greenpeace staged Thursday a protest against the storage of dangerous substances at a red mud reservoir in Hungary like the one where a massive spill killed 10 people last year.
About two dozen activists from the environmental pressure group stretched out a banner of 73 by 213 metres (240 by 700 feet), displaying the single word "STOP", above the resevoir, an AFP photographer said.
"The reservoir is close to river Danube, its wall serves as a dyke against floods. Its composition and stability are less than adequate, according to our knowledge," activist Balazs Tomori said, demanding an "immediate check."
A similar reservoir burst on October 4, 2010 in western Hungary, killing 10 people as a million cubic metres (40 million cubic feet) of toxic mud cascaded into surrounding villages.