DAMASCUS- An explosion believed to have been caused by a car bomb tore through a Syrian refugee camp at a border post on the frontier with Turkey on Thursday, Feb. 20, killing five people, a monitoring group said.

Ambulances ferried the injured from the refugee camp to the southern Turkish city of Kilis, where a state hospital official said at least 40 people were being treated.

A Turkish border official said the blast near Turkey’s Oncupinar border post, which sits opposite the Syrian Bab al-Salameh gate, could be felt several kilometers away, but that the border gate remained open.

Amateur video posted on the Internet showed what appeared to be three bodies under blankets. The Syrian Observatory for Human Rights monitoring group said five people were confirmed dead and a fire broke out in the camp after the blast.

Thousands of Syrians have been fleeing the city of Aleppo, some 60 km (40 miles) south of Kilis, in recent weeks because of a campaign of improvised “barrel bomb” attacks by President Bashar al-Assad’s forces.

Many of the displaced live at a makeshift camp on the Syrian side of the border. Thursday’s blast hit this area, according to video footage.

Towns near Bab al-Salameh have also seen sporadic clashes between the rebels fighting Assad and fighters from an al-Qaeda splinter group, the Islamic State of Iraq and al-Sham (ISIS).

Abu Osama, a camp administrator, said the explosion happened behind his office and at least 20 tents were reduced to rubble. “Some of the bodies and tents melted from the explosion,” he said over the phone. “We have had thousands of new refugees come to this area the past 20 days because of the barrel bombing in Aleppo.”

He blamed the attack on militants from ISIS and said it had fired several rockets near the camp over the past few days where members of the rival Islamic Front rebel group are based.