There was anger after the military began moving loyalists away from the area
The tombs of four Ugandan regional kings have been wrecked by fire, sparking protests and claims of arson.
Thousands of people poured on to the streets of Kampala and eyewitnesses said at least one person was killed after security forces opened fire.
Police denied anyone had been hurt and said the cause of the fire was unknown.
The Unesco-listed site housed tombs of kings of the Buganda region. The kingdom has had uneasy relations with the central government recently.
A dispute over territory between King Ronald Mutebi and President Yoweri Museveni led to mass riots late last year.
Eyewitnesses say Mr Museveni tried to visit the Kasubi tombs near Kampala to see the extent of the fire damage, but supporters of the king blocked his convoy.
The BBC's Joshua Mmali, at the scene of the fire, says people have been mourning the loss of the monuments.
Police are investigating the cause of the fire
He says the tombs are revered among some people in the Buganda region as a symbol of what had traditionally belonged to their kingdom.
The tomb's custodian, Fred Mukasa, described it as a sad loss for the whole kingdom.
"We have lost our treasured culture, this is the origin of all the Buganda culture, this is where our ancestors are buried."
Police chief Maj Gen Kale Kayihura told AFP news agency that the emergency services had been "obstructed by a hostile crowd" when they arrived at the scene.
FROM GLOBAL VOICES
This relationship between President Museveni's government and Buganda Kingdom is far from rosy and this has already given fertile ground for many to think there was some foulplay. Many people seem to expect riots... We only hope there will be a thorough investigation... and that no people will lose their lives and property.
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