Syrian rebel forces killed a pro-regime Sunni cleric in the city of Aleppo, with some reports suggesting he was beheaded, and then dragged his body through the streets, a watchdog group said on Saturday.

Sheikh Hassan Seifeddin, imam of a mosque in the northern Aleppo neighborhood of Sheikh Maqsud, "was killed overnight Friday by rebel fighters in the east of the area and his body was dragged through the streets," the Syrian Observatory for Human Rights said.

The latest affliction to hit weary residents of Aleppo is written on their faces. Some call it the "Aleppo button", a welt caused by leishmaniasis, an illness that is sweeping the Syrian city.

Transmitted by flies, the parasitic disease arrived along with the thousands of Syrians displaced from their homes by fighting.

Syrian rebels have seized a key town on a main highway between Damascus and the south in their latest advance in Daraa province on the border with Jordan, a watchdog said on Friday.

"Rebels seized control of Dael after destroying the three army checkpoints at the entrances to the town," the Syrian Observatory for Human Rights said. "The town is located on a main road linking Daraa to Damascus."

A top diplomat on Friday condemned the move by the Gulf state of Qatar to let Syria's opposition open an "embassy" in Doha, calling the decision "hasty and irrational," Iran's official IRNA news agency reported.

"Qatar's theatrical act in giving the Syrian embassy to a group which is unelected is both hasty and irrational," the deputy foreign minister in charge of Arab and African affairs, Hossein Amir Abdollahian, was quoted as saying.

U.S. State Department spokeswoman Victoria Nuland said late Thursday it remained unclear who was behind a mortar attack that left at least 15 students dead at Damascus University, after Syrian state media blamed "terrorists."

But she urged both sides to be "absolutely vigilant in avoiding attacks on civilians and to ensure that their actions are in accordance with international law."

A mortar attack that killed 15 students at Damascus University marks a rebel escalation in the Syrian capital ordered by foreign governments, Information Minister Omran al-Zohbi said on Friday.

"The terrorists' mortar attacks on residential areas, schools, universities and hospitals is the result of foreign orders to stage a full-scale escalation," Zohbi told state news agency SANA.

French President Francois Hollande has backed off a push to arm Syrian rebels amid turmoil within Syria's opposition and concerns the weapons could fall into extremist hands.

France has been pressuring European Union partners to lift an arms embargo against Syria to be able to provide the rebels with firepower against President Bashar Assad's military.

Syrian rebels have seized a key town on a main highway between Damascus and the south in their latest advance in Daraa province on the border with Jordan, a watchdog said on Friday.

"Rebels seized control of Dael after destroying the three army checkpoints at the entrances to the town," the Syrian Observatory for Human Rights said. "The town is located on a main road linking Daraa to Damascus."

A former U.S. soldier has been arrested and charged with terror offenses after he allegedly traveled to Syria and joined an al-Qaida-linked rebel group, the Justice Department said Thursday.

Eric Harroun, a 30-year-old army veteran from Phoenix, Arizona, is alleged to have joined a squad of guerrilla fighters from the Al-Nusra Front, training to use rocket-propelled grenades against Syrian government forces.

A Syrian boat entered Lebanese territorial waters and opened fire on a Lebanese fishing boat off the northern coast of Arida, injuring a fisherman, the state-run National News Agency reported Friday.

NNA identified the fisherman as Khaled Ahmed al-Ali. Media reports said he was injured in the leg.