Gangs on the tiny Pacific island of Nauru have attacked its main police station during a protest.
Several people have been arrested as a result of the unrest, but the cause of the violence is still unclear.
There has been recent tension over claims officials ignored corruption allegations, but a more likely explanation is a dispute over mining.
Australia has warned of the risk of more violence and has sworn in about 100 civilians for extra security.
Nauru is the world's smallest independent nation. It is located halfway between Australia and Hawaii.
These are times of great uncertainty for Nauru's population of 13,000 residents, says BBC Sydney correspondent Phil Mercer.
They were once among the world's richest people on a per-capita basis.
But over the years they have seen most of their money disappear in poor government investments. The unemployment rate is estimated to be about 90%.
The closure of an Australian-sponsored immigration detention centre has added to the island's financial difficulties.
The government has re-opened parts of the old phosphate mines in an attempt to revive the economy.
Disagreements over payments to landowners could well lie at the heart of the weekend's unrest, our correspondent says.
A New Zealand government spokesman said the situation on Nauru was calm, although Australian officials have warned that further instability is possible.
The island suffers high rates of obesity and endures regular power failures. The country's airline has been repeatedly grounded, and it has been reported that one plane was even wheel-clamped because of unpaid bills.