( CNN ) They took Yarmouk by storm , a sea of masked men flooding into the streets of one the world 's most beleaguered places . Besieged and bombed by Syrian forces for more than two years , the desperate residents of this Palestinian refugee camp near Damascus awoke in early April to a new , even more terrifying reality -- ISIS militants seizing Yarmouk after defeating several militia groups operating in the area . `` They slaughtered them in the streets , '' one Yarmouk resident , who asked not to be named , told CNN . `` They ( caught ) three people and killed them in the street , in front of people . The Islamic State is now in control of almost all the camp . '' An estimated 18,000 refugees are now trapped inside Yarmouk , stuck between ISIS and Syrian regime forces in `` the deepest circle of hell , '' in the words of U.N. Secretary-General Ban Ki-moon . Yarmouk , the largest Palestinian refugee camp in Syria , was formed in 1957 to accommodate people fleeing the Arab-Israeli conflict . The camp , which sits just 6 miles from central Damascus , has been engulfed in fighting between the Syrian government and armed groups since December 2012 . The London-based Syrian Observatory for Human Rights says ISIS and the al Qaeda-affiliated Al-Nusra Front control about 90 % of the camp . The organization also claims that the Syrian government has dropped barrel bombs on the camp in an effort to drive out armed groups . Activists and residents in Yarmouk tell CNN that as many as 5,000 people have tried to flee their homes since ISIS stormed the camp , but have no place to go . Hundreds have been injured , but the camp 's only functioning hospital was first occupied by ISIS , then targeted last week by regime shelling . As the fighting raged in Yarmouk , the director of the Jafra Foundation -- the only aid group that has been able to get into the camp -- painted a grim portrait of the conditions on the ground since ISIS arrived . `` We need medicine and access to treatment and medical facilities , '' Wesam Sabaneh told CNN . `` The last hospital in Yarmouk camp was bombed yesterday , so there 's really nothing functioning . '' Opinion : Save the 'miracle babies ' Even delivering clean water in Yarmouk can be a deadly task . Majed Alomari , the Jafra Foundation 's water coordinator , was killed a few days ago -- gunned down in an ISIS firefight with rival rebel groups . The head of the Palestinian League for Human Rights in Syria ( PLHR ) , who fled the camp and Syria in October 2012 , said the people of Yarmouk were in dire need of help . `` According to my contacts inside , people are back to consuming water with spices -- a common meal used in 2014 '' during the Syrian regime 's siege of the camp , the PLHR 's Salim Salamah told CNN . Aid agencies briefly managed to break the government 's stranglehold on the camp last year , and delivered aid to tens of thousands . But now , as terror closes in on Yarmouk from all sides , residents have two choices -- to attempt to flee what was their place of refuge , or to stay inside what the U.N. says now resembles a camp of death . `` Now I am scared of two things -- I am scared of ( ISIS ) and the regime , '' the Yarmouk resident told CNN . `` The regime now is about to destroy the Yarmouk camp , '' he said . `` And ISIS , I do n't know ... they did n't do anything except [ rename ] Yarmouk Camp as 'Yarmouk Islamic State . ' ''
ISIS has seized control of large parts of the Yarmouk Palestinian refugee camp in Syria . one refugees are trapped between militant groups and regime forces . U.N. : `` In the horror that is Syria , the Yarmouk refugee camp is the deepest circle of hell ''