Médecins Sans Frontières has said it has suspended most of its medical aid activities in northeast Syria.
The body said it was evacuating all international staff in the wake of air strikes and violence during Turkey's week-old incursion.
"The decision to suspend the majority of MSF's activities comes as the humanitarian situation spirals further out of control and needs are likely to increase," MSF said.
It follows another aid group, Mercy Corps, suspending its aid work yesterday.
Speaking to RTÉ News, the Emergency Manager for Syria with MSF said it was not an easy decision to take, especially when they see the crisis in the region getting worse.
Robert Onus said: "Northeast Syria is a space where there are already 100,000 people living in displacement camps.
"Now on top of that, you have all of these newly displaced people fleeing from the border region with little more than the clothes on their back."
Mr Onus said that they were "extremely worried" about what the future holds for those people as they were hugely reliant on humanitarian assistance.
'It is a really difficult decision and we are extremely worried about what the future holds for those people' – Robert Onus of @MSF spoke to @jackiefox_ about the organisation’s decision to withdraw from northeast Syria | Read more: https://t.co/CFOzOEGLlE pic.twitter.com/AwQGaOh9IB— RTÉ News (@rtenews) October 15, 2019
No MSF workers are reported to be injured from the attacks in the region.
However, Mr Onus said they could not be confident that their staff were safe in northeast Syria.
He also said MSF did not have assurances that you need in order to deliver humanitarian assistance in a conflict zone.
Staff working with MSF were working in hospitals and were moved numerous times due to shelling.
"It became a process where you can relocate so many times before you need to take the decision to say 'this is not possible'," Mr Onus said.