The Solomon Islands capital Honiara was placed under curfew Wednesday after protesters attempted to storm the Pacific island nation's parliament, police said.
Police fired tear gas at the protesters, who had set alight buildings, partly burning down a police station and a hut near the parliament building, a police spokesman said.
He was unable to confirm witness accounts that the protest was a failed attempt to topple Prime Minister Manasseh Sogavare.
"A crowd formed in front of the parliament, I don't know the exact numbers but it was a huge crowd," he told AFP.
"They intended to make the prime minister resign, that's the public speculation, but we're still investigating the motives.
"The important thing is police now have control of the situation and no one is out on the streets."
He said police were unaware of any injuries.
Video footage shot by onlookers showed police and protestors facing off along a street and columns of smoke rising from torched buildings.
Images on social media also showed crowds looting food from local stores.
Honiara resident Jeremy Gwao said people in the capital were fearful after the dramatic events.
"Many didn't know there would be a protest and were shocked," he said.
"There were hundreds and hundreds on the street... and their main aim was to get the PM to step down.
"It was a scary situation and it's still tense. People at the moment don't know what's going to happen and police are trying to keep everything calm."
Canberra's official Smart Traveller advice service warned Australian nationals in the Solomons capital to be vigilant.
"The situation is evolving in Honiara with civil unrest. Please exercise care, remain where you are if it is safe to do so and avoid crowds," it said.
The violence reportedly involved a group of protesters who travelled to Honiara this week from the neighbouring island of Malaita.
Their grievances are believed to involve perceived neglect by the central government and lingering dissatisfaction at the Solomons' decision to switch diplomatic allegiances from Taiwan to China in 2019.
Many communities in Malaita had forged deep ties with Taipei and the island's local government has repeatedly complained about embracing China.
Such inter-island tensions spurred unrest that led to the deployment of an Australian-led peacekeeping force from 2003 to 2017.
There was rioting following general elections in 2006, with much of Honiara's Chinatown razed amid rumours businesses with links to Beijing had rigged the vote.
Honiara-based lawmakers from Malaita issued a statement this week calling for protesters from their home island to refrain from violence.
"The devastating consequences that such actions will have on our people and future will take this country back 20 years," it said.
Sogavare's office has been approached for comment.