The Netherlands is sending more forces to contain "serious" post-storm looting on the island of St Martin as Hurricane Irma leaves a trail of destruction.
Prime Minister Mark Rutte said more soldiers and police would be deployed amid reports of people with guns and machetes roaming the streets.
A French minister said she witnessed looting close up. The island is shared between France and the Netherlands.
At least 17 people across the Caribbean have been killed by Hurricane Irma.
The hurricane has been downgraded to a category four, but US officials have warned that it remains "extremely dangerous".
The storm has recently pummelled the Turks and Caicos Islands - a British overseas territory which has experienced a top-rated category five hurricane for the first time.
It is now hitting Cuba and the Bahamas. Some 500,000 people were told to leave south Florida ahead of its arrival there on Sunday.
Nine people are now known to have been killed and seven are missing in the French territories of St Barthelemy and St Martin, French Interior Minister Bernard Collomb said.
Damage to property on St Martin is extensive with rooftops shredded, boats ripped to pieces and electricity pylons overturned. Most of the island's 80,000 residents have lost their homes.
The French government said two-thirds of houses on the island have been left uninhabitable, with no electricity, drinking water or gasoline available. It too is sending navy frigates, planes and helicopters.
Annick Girardin, minister for France's overseas territories, described "scenes of pillaging", urging police to restore order and provide emergency care for victims.
"We need to restore public order to Saint-Martin," she said.
"I was out this morning and this afternoon and there was looting right there in front of my eyes. There is a strange mood at the moment in Saint-Martin, so we need to think about public order."
The UK has declared an emergency in the Virgin Islands and had deployed troops in its Overseas Territory of Anguilla, which has also suffered extensive damage.
Which other areas have already been hit?
- The Turks and Caicos Islands: widespread damage, although extent unclear
- Barbuda: the small island is said to be "barely habitable", with 95% of the buildings damaged. Prime Minister Gaston Browne estimates reconstruction will cost $100m (£80m). One death has been confirmed
- Anguilla: extensive damage with one person confirmed dead
- Puerto Rico: more than 6,000 residents of the US territory are in shelters and many more without power. At least three people have died
- US Virgin Islands: damage to infrastructure was said to be widespread, with four deaths confirmed
- Haiti and the Dominican Republic: Both battered by the storm, but neither had as much damage as initially feared
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