The coordinating committee of Yarmouk refugee camp told Ma'an that four Palestinians were killed at a security checkpoint near the city of Aleppo.

Their bodies were found on the street and showed indications of an execution style killing, according to the group. Two other Palestinians were shot dead in their Damascus homes, it said.

Hussein al-Masri, Muhammad al-Jadaa, Hikmat Darbas al-Nayrab and Hassan Salameh, all from Nayrab refugee camp, were named as those killed in Aleppo.

Raed Hjouj and Ammar Abbas were killed in Yelda, Damascus.

Palestinian Authority Ambassador to Syria Mahmoud al-Khalidi reiterated to Ma'an on Wednesday that the PLO would not intervene in the Syrian conflict.

"Efforts are still there to maintain non-interference in the internal affairs of Syria," he said.

The consensus was confirmed during a meeting of Palestinian factions in Syria, al-Khalidi added.

Yarmouk is an unofficial camp for Palestinian refugees. The densely populated, impoverished district in southern Damascus is packed with concrete buildings.

Last week, at least 18 Palestinians were killed and their bodies displayed publicly in Damascus, PLO officials in Yarmouk said.

The PLO office said the Syrian regime "committed a massacre" against Palestinians in the camp. Bodies were found mutilated and charred, it said.

This summer, many districts of southern Damascus became a daily battleground in an 18-month-old popular revolt against Bashar Assad that has escalated into civil war.