The Greek government said Friday it would extend a lockdown imposed on migrants living in camps on its Aegean islands and eastern frontier until September 15 as coronavirus cases mount.
Lockdown was first ordered in the camps on March 21.
Authorities are particularly concerned about the virus' spread in camps on five Aegean islands.
The facilities were designed to hold fewer than 6,100 people, but at present 24,000 are crammed into them in unsanitary conditions.
Athens decided to extend the lockdown "to prevent coronavirus cases from appearing and spreading," the migration ministry said.
But charities have repeatedly condemned the government for continuing to keep asylum seekers in accommodation that makes keeping up hygiene measures extremely difficult.
New arrivals on the islands are currently being quarantined in separate buildings to limit the risk of contaminating entire camps.
Lockdown at first led to slowing numbers of arrivals, but they have inched back up over the summer.
On the night of Thursday to Friday, the Greek coastguard rescued a sailing ship off the island of Rhodes that was transporting 55 people.
On Wednesday, harbour police picked up 96 people whose ship had got into difficulty off the island of Halki, and the search has carried on into a third day for a 35-year-old man and his four-year-old son lost as the ship sank.
With just 254 deaths from Covid-19, Greece has suffered less from the virus than other European countries, and so far no-one has died of the disease in a migrant camp.