Syria: Yarmouk refugee camp hit by mortar attack, 21 killed

Syrian activists today said 21 people died in a mortar attack on the Yarmouk Palestinian refugee camp in Damascus, the Associated Press reported.

The UK-based Syria Observatory for Human Rights told AP shelling started late Thursday as people were buying food for the evening meal. 

"We don't know where the mortars came from, whether they were from the Syrian regime or not the Syrian regime," the rights group head, Rami Abdul Rahman, told AP. 

More from GlobalPost: Inside Syria: Free Syrian Army and Assad forces clash over 10th Street in Aleppo

Syrian state media said the attack was the work of "terrorist mercenaries," said AP, a term seen as a veiled reference to armed rebels that have been trying to overthrow the government for the last 17 months. 

Online videos cited (but not verified) by AP show camp residents protesting against the government just before Thursday's attack, chanting anti-Assad slogans and showing support for the opposition Free Syrian Army. 

The conflict between the regime and rebels has wrought a full-on humanitarian crisis, with over 15,000 people dead according to the UN, and hundreds of thousands forced to flee their homes. The international community has not been able to unite behind a plan to help end the crisis, with the United Nation's key negotiator, Kofi Annan, resigning Thursday.

Annan explained the move in a lengthy Financial Times article that concluded by saying the only way to save Syria is "courage and leadership, most of all from the permanent members of the Security Council, including from Presidents Putin and Obama."

The US president has reportedly just signed an order that officially allows the CIA to assist the Syrian rebels, according to The Guardian.  Britain's foreign secretary, William Hague, has also announced that the government has been aiding the opposition in a "practical and non-lethal way."

Annan believes such efforts need to be discussed and coordinated internationally in order to achieve a peaceful transition of power. "Is ours an international community that will act in defense of the most vulnerable of our world, and make the necessary sacrifices to help?" he wrote. "The coming weeks in Syria will tell."

Syrian rebels say they are sure they will win eventually. Free Syrian Army rebel commander Ahmed Mustafa Almohammad told FOX News today that the "regime will fall, and we will finish them," but warned that "continued lack of international support will push the ordinary people to the extremists."

His comments come amid growing concern of Al-Qaeda's presence in Syria (TIME: "Meet the Islamist Militants Fighting Alongside Syria’s Rebels.")

But Almohammad, who spoke to FOX through an interpreter on Skype in Syria, said the rebel group "will not allow any of our people to go to Al Qaeda and other extremist groups."