File photo shows a Palestinian boy targeted in a militant attack in the Damascus-based Yarmouk refugee camp.
Palestinian refugees in the Syrian capital have demanded militants to withdraw from the Yarmouk camp as fresh fighting flares at the Damascus-based refugee site.
Four residents died when a shell fired by the foreign-backed militants struck the camp on Tuesday. Another person was shot dead by a sniper.
Meanwhile, new footage posted on the Internet shows militants shooting down a civilian airplane in the eastern Deir ez-Zor governorate.
There were no immediate reports on the number of casualties.
Militants from the al-Qaeda-linked al-Nusra Front have also reportedly executed three Syrian soldiers kidnapped in the eastern city of Deir ez-Zor.
In the northwestern governorate of Idlib, militants attacked the Taftanaz military airport.
According to Syria's official news agency, SANA, army units in Idlib's provincial capital managed to kill all the members of two militant groups with the assistance of locals, and seized their weapons.
Since mid-March 2011, Syria has been experiencing a deadly unrest, which has killed many people including large numbers of security personnel.
Damascus says the violence is being orchestrated from outside the country, while reports indicate that a large number of the militants fighting the Syrian government are foreign nationals.
Several international human rights organizations have blamed foreign-sponsored militants for committing war crimes.