Police fired warning shots and used tear gas, they "beat up" some of those demonstrating, an NGO told Euronews.
Police clashed with residents from a refugee camp on the Greek island of Samos on Saturday morning, an NGO has told Euronews.
The refugees and asylum seekers were staging a protest march about living conditions in the camp but had their route blocked by police at around 7.30 am local time, a member of the NGO said.
"There were no more than 60 to 70 people there, they were one-on-one with police," they added.
Police fired warning shots and used tear gas and "beat up" some of those demonstrating, according to the NGO.
One refugee sent an image to Euronews that showed his back with two marks across it (pictured in the main image of this article).
"Things in Samos aren't working well, that's why we went on the march," he said.
"I saw police charge at the protesters," Jerome Fourcade, an independent photo journalist based in Samos, told Euronews.
Around 10 NGO workers were taken in by police at the scene of the clashes at 8.30am and held for a number of hours: "They said they were verifying our ID cards," one said.
Fourcade was also detained by police when he tried to photograph those demonstrating.
Authorities asked to look at his photographs, but he refused arguing that he had not been arrested so they did not have the right.
He was released around 10.30 am once all the residents had returned to the refugee camp.
Overcrowding is a serious issue in the Samos camp, which is designed to host a maximum of around 650 people, while there are roughly 4,000 people living there and in the "jungle" surrounding it.
Most people have no direct access to sanitation and live in flimsy tents or shelters they built themselves, the NGO worker said.
"They are surrounded by pests — barely a day goes by when I'm not sent a photo of someone who has found a snake in their tent or been bitten by a scorpion or a rat," they added.
"The camp is overflowing with garbage, it's 26 degrees today, so it's festering ... these are extremely inhumane conditions."
This is not the first time the inhabitants of the camp have demonstrated, with three peaceful protests taking place in January along with another that turned violent, although "nothing as bad as this," according to the NGO.
Saturday marked the first time police used tear gas on the asylum seekers and refugees, it said.
A police spokesman for the North Aegean islands told Euronews that a group of 100 migrants attempted to march into the city to protest about living conditions in and around the camp.
"They were stopped by the police and there was some tension," he added. The spokesperson is based in Lesbos and said he did not know anything about the use of tear gas or the police detentions.
The clashes came a day before Greeks were set to vote in both the European Parliamentary elections and the first round of the municipal elections, when mayors and regional governors are appointed.
The NGO did not want to be named in this article and its workers did not wish to be identified.