Beirut: A large blast hit a neighbourhood of the Syrian city of Aleppo on Friday and caused several casualties, state television said.

It was unclear who was behind the attack.

Syria TV said the explosion had been caused by a rocket fired by a “terrorist group” - a term it frequently uses to describe rebels in the 22-month-old uprising against President Bashar Al Assad.

But opposition groups said Al Assad’s forces were behind the blast, which hit the Muhafaza Sakaniya neighbourhood in a western district of the city.

Video from state television showed the side of a building collapsed into rubble that spilled into nearby streets. A crowd sifted through the wreckage as medics pulled bloodied bodies onto stretchers.

Activists said the district, a government-held area of a city that has descended into a long and bloody stalemate between army and rebels, had been hit by a military air strike.

“The rebels do not have this capability yet,” said Hameed Barrasho, an activist in Aleppo speaking by Skype. “We have several reports of a jet in the area before the strike. This is the regime trying to sow more chaos in the city.”

Syria’s government restricts foreign media access to parts of the country it holds, making it difficult to confirm accounts by either side.

Earlier in the week, twin blasts at the University of Aleppo killed more than 80 people. Each side blamed the other.

Meanwhile, fierce clashes raged in the majority Kurdish northern Syrian city of Ras Al Ain on the Turkish border, a day after a sniper killed a French journalist in embattled Aleppo.

The Syrian Observatory for Human Rights confirmed Yves Debay’s death on Friday, after Aleppo-based activists accused regime troops of the shooting, and distributed photographs of his body and press card.

The fighting in Ras Al Ain came six months after troops loyal to President Bashar A Assad withdrew from majority Kurdish areas, leaving residents to fend for themselves.

Jihadists have since staged several assaults on the strategic city, and most of its residents have fled.

Syria’s Kurds are divided over the revolt against Al Assad - some support the regime, others back the revolt and yet others are striving to stay neutral.

On Friday, fighters from radical groups Al Nusra Front and Ghuraba Al Sham battled Kurdish militiamen a day after launching a new assault on the border town, residents and activists said.

On Thursday, “the fighting became more intense in the evening after Kurdish fighters received reinforcements to try to stop the fiercest rebel assault ever since insurgents first arrived in the city” in November, a resident identifying himself only as Mohammad told AFP.

Al Nusra Front is listed by the United States as a “terrorist” organisation.

A Kurdish resident of Ras Al Ain, who said he opposed Al Assad’s regime, said the jihadists crossed the Turkish border with three tanks into Ras Al Ain on Thursday.

“The Kurdish fighters have seized one of the tanks,” the activist, who identified himself as Havidar, told AFP via the Internet.

While Turkey supports the revolt against Al Assad, it is also home to a sizeable Kurdish minority that has suffered much persecution and suppression.

Activists say they fear Turkey may be using jihadists in Syria to fight its own battle against the Kurds.

“The advancing rebels did not use the tanks to fight the regime. Instead, they used them to shell Ras Al Ain,” Havidar said.

Analysts and activists have voiced fears over the potential consequences if the fighting between Kurdish militia and jihadists continues.

“Should the fight morph into a struggle between Kurds and Arabs... Syria and the revolt [against Al Assad] are both in real danger,” said prominent Kurdish activist and journalist Massoud Akko.

Westwards in Aleppo, the Observatory on Friday confirmed the death a day earlier of Belgian-born French journalist Debay, a killing activists blamed on the regime.

“He was killed on one of Aleppo’s fronts” on Thursday, said the Aleppo Media Centre, adding that he was “shot by a regime sniper.”

Anti-regime activists in the city posted online photographs of Debay’s body and of his press card, as well as an amateur video showing the corpse.

“It is not exactly clear how he was killed, but it seems like he entered a very dangerous street where the army and pro-regime militia were positioned,” said an activist who spoke to AFP on condition of anonymity.

At least 17 professional journalists, both foreign and Syrian, and 44 citizen journalists have died reporting on one of the deadliest wars for the media in recent years, according to figures from watchdog Reporters Without Borders.

Debay’s death was confirmed a day after 142 people were killed across Syria, among them 72 civilians, said the Observatory.

Syria’s spiralling conflict has killed more than 60,000 people in less than two years, says the UN. The Observatory has documented 48,000 dead, most of them civilians.