All must return to their ancestral lands. No one has the right to deny their claims to Palestine. As for the attack it was most likely perpetrated by the opposition or so called "rebels" who are nothing more than a bunch of foriegn trained terrorist. The have no support from Syrians. Syrians wanted change but not at any price. The pig headed Arab nations of Saudi Arabia and Qatar hijacked an organic peaceful movement and turned it into a bloody war.
U.S., allies conduct 1 air strike in Syria and 11 in Iraq against ISIS militants (Reuters)
from the article: Syrian government attack forces Palestinian exodus from Damascus camp