Turkey's military operations in the south-east, which includes strict curfews on civilian areas and the denial of access to medical care and water, amount to "collective punishment," Amnesty International warned on Thursday.
The London-based human rights group, which said it carried out research on the ground in the affected areas in the mostly Kurdish south-east, cautioned about "extreme hardships they are currently facing as a result of harsh and arbitrary measures."
Amnesty said its research in Kurdish areas, some of which are inaccessible to international observers, found Turkey's "onslaught on Kurdish towns and neighbourhoods ... is putting the lives of up to 200,000 people at risk and amounts to collective punishment."
"Cuts to water and electricity supplies combined with the dangers of accessing food and medical care while under fire are having a devastating effect on residents, and the situation is likely to get worse, fast, if this isn't addressed," said John Dalhuisen, Amnesty's programme director for Europe and Central Asia.
A two-year ceasefire between the armed Kurdistan Workers' Party (PKK) and the state broke down in July, leading to a fresh outbreak of violence in the south-east, especially in Diyarbakir and Sirnak provinces.
Last month, the government launched an intense operation in those two provinces aimed at rooting out the PKK and its allied offshoots, using police and the army.
The army says security forces have since killed nearly 600 militants in the areas. Dozens of members of the security forces also died.
Kurdish officials say 100 civilians have been killed since last month in the two provinces, including 18 children.
Additionally, more than 150 people have died in areas under curfew during fighting between government forces and the PKK's armed youth wing, the Patriotic Revolutionary Youth Movement (YDG-H), Amnesty said.
Amnesty said the government forces were using heavy weaponry and snipers, while preventing many observers from reaching affected areas.
"While the Turkish authorities can take legitimate measures to ensure security and arrest suspects, they must comply with their human rights obligations," Dalhuisen said.
"The operations currently being conducted under round-the-clock curfews are putting the lives of tens of thousands of people at risk and are beginning to resemble collective punishment."
"In some areas, crippling curfews that don't allow people to leave their houses at all have been in place for more than a month, effectively laying siege to entire neighbourhoods," said Dalhuisen.
"It is imperative that the Turkish authorities ensure that affected residents are able to access food and essential services," he said.
The government views the PKK as a terrorist organization and Prime Minister Ahmet Davutoglu said his objective is to "clean" the areas of the militants.