Athens, Greece - At least 148 asylum seekers at a hotel in Greece managed by the International Organization of Migration have tested positive for COVID-19.

The hotel, in the southern town of Kranidi, hosts around 450 asylum seekers, most of whom are from Africa.

After visiting the site on Tuesday, Deputy Civil Protection Minister Nikos Hardalias told reporters that 150 people tested positive overall - at least 148 were refugees, one was an aid worker and the other was the employee. All were asymptomatic, he said.

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A 28-year old woman from Somalia who lives at the hotel, who is six months pregnant, was tested for the virus during a visit to the Hospital of Nafplio on Sunday and was confirmed as positive for COVID-19 on Monday.

The hotel has been quarantined since last week when a staff member tested positive for COVID-19. It was not clear whether this staff member was the same person Hardalias referred to on Tuesday.

Refugees gather on their balconies at the hotel in Kranidi, which hosts about 450 asylum seekers and was placed in isolation on Monday after a pregnant resident tested positive for the new coronavirus during a hospital visit [Thanassis Stavrakis/The Associated Press]

There are currently two refugee camps in Greece with confirmed cases of COVID-19.

On April 2, the Ritsona refugee camp with a population of 2,700, became the first in the country to have positive cases among residents, when a woman who had recently given birth in the local hospital tested positive.

Ritsona was subsequently put under quarantine for two weeks with no residents permitted to leave.

At the time, IOM told Al Jazeera that hygiene kits, food and medical supplies would continue to be distributed to the residents.

Nearly three weeks later, the refugees and migrants there are still in quarantine and were expecting an update on the situation in the coming days, Parwana Amiri, a 16-year old Afghan resident of the camp, told Al Jazeera.

On April 5, the Malakasa camp, around 24 miles north of Athens, was also placed under quarantine measures after a 53-year-old Afghan resident tested positive.

Greece, which swiftly implemented strict lockdown measures for its citizens, has fared better than many of its neighbours, with a death toll of just 116 as of Monday.

But fears are growing about the potential impact of the virus sweeping through refugee camps, particularly in overcrowded sites on the Aegean islands.

Only a small number of cases have been confirmed among the local island populations, but to date none in any of the refugee camps.

On the island of Lesbos, the Moria refugee camp has a population of around 19,000 in a space designed for just under 3,000.

Medical charity Doctors Without Borders has repeatedly called for the urgent evacuation of the camp.

"In some parts of Moria camp, there is just one water tap for every 1,300 people and no soap available. Families of five or six have to sleep in spaces of no more than 3m2," Dr Hilde Vochten, MSF's Medical Coordinator in Greece said in a statement.

"This means that recommended measures such as frequent hand-washing and social distancing to prevent the spread of the virus are just impossible."

On Sunday, a fire tore through the Vial refugee camp on the island of Chios where 5,000 people live in a space designed for just over 1,000.

The fire started during protests after the death of a 47-year-old Iraqi woman in the camp, who had been taken to hospital exhibiting symptoms of COVID-19 but had tested negative.

Her cause of death is unknown but according to reports, despite the negative test, residents believed she died of the virus and this fear prompted the protests.

On Monday, Notis Mitarakis, Greece's Minister for Migration, announced that around 1,500 of the most vulnerable people living in the Moria camp would be evacuated on a specially chartered ship to the mainland by the end of this week.

A plan to move 1,600 unaccompanied refugee children from the island camps was set in motion last week as 12 children arrived in Luxembourg and 47 went to Germany - a development criticised by figures such as Erik Marquardt, a German member of the European Parliament for the Greens Party, who tweeted that the small number was an "embarrassment".