Greece has sent extra riot police to the resort island of Kos as tensions mount over an influx of migrants and refugees, police say.
The deployment came on Wednesday (local time) after the island's mayor, Giorgos Kiritsis, warned of "bloodshed" if the situation on the island of 33,000 people - where around 7000 migrants are waiting to apply for immigration papers - worsened.
"Two units, or 40 men, have arrived in Kos. Other reinforcements are being sent from other eastern Aegean islands," a police spokesman said.
On Tuesday, police beat back migrants with truncheons and sprayed them with fire extinguishers to prevent a stampede as migrants, mostly Afghans and Syrians, were being relocated to a local football stadium after camping along roads and beaches for weeks.
Local media reports said 250 extra police were being deployed on islands, where migrants crossing by sea from nearby Turkey have landed.
Mayor Kiritsis, who on Tuesday said there "was a risk of bloodshed if the situation degenerates", said the situation had "calmed" on Wednesday but was still tense as thousands of migrants await registration.
Greek Prime Minister Alexis Tsipras last week said the refugee crisis "surpasses" the crisis-hit nation's resources and called for European Union assistance.
"Since the beginning of the week extra immigration officials have been sent to Kos to speed up the administrative procedure," said Kiritsis.
"We hope that by Friday, the majority of the migrants can be registered and can leave the island."
The UN refugee agency's division for Europe said last week that 124,000 refugees and migrants had landed in Greece since the beginning of the year.
The agency said that Athens' response to the problem had so far been "totally shameful", with many of those landing on the eastern Aegean islands near Turkey forced to sleep in the open, without access to washing facilities and toilets.