Syrian rebels have seized control of a hospital used as a headquarters by an al Qaeda affiliate in the northern city of Aleppo, part of a widening campaign against the extremist group in the country's opposition-held north, activists said.
The capture of the hospital Wednesday (local time) underscores the intensity of the rebel infighting that has raged for days between a consortium of Syrian rebel groups and their one-time allies, fighters from the Islamic State in Iraq and the Levant.
A spokesman for the group vowed to crush the rebel groups attacking it.
"Know that we have armies in Iraq and Syria ... we warn you," said the spokesman known as Abu Mohammed al-Adnani in an audio clip posted on militant websites overnight. "We will crush them and kill the conspiracy in its cradle."
The spokesman also declared war against Shiites in Iraq, Syria, Lebanon and Yemen, whom Sunni Muslim extremists consider to be their main enemy.
A chaotic mix of rebel groups in Syria, including Islamic factions, turned their guns on fighters of the "Islamic State" last Friday. The clashes have since become the most serious rebel infighting since the uprising against Syrian President Bashar Assad began in March 2011.
The rebel-on-rebel fighting began after tensions, which had simmered for months, boiled over following reports that the al Qaeda fighters had tortured and killed a popular doctor.
The fighting since has spread from the northern province of Aleppo to nearby Idlib and to the province of Raqqa, a bastion of the "Islamic State." At least 300 people have been killed in the infighting in the past five days, said Rami Abdurrahman, the head of the Britain-based Syrian Observatory for Human Rights.
The capture of the hospital was a boost for the rebels, who only the day before saw 20 of their fighters killed in an al Qaeda suicide car bombing in the northern city of Darkoush, according to activists.
The Observatory and other activists reported that dozens of detainees held by the extremists had been freed. The Aleppo Media Center estimated the number to be around 300.
One of the most pressing issues in the rebel infighting is the fate of dozens of Syrian and foreign reporters, media activists, aid workers and civilians abducted and held by the al Qaeda fighters since they fanned into the area in March. On Tuesday, the Observatory and other groups reported that at least four activists detained in the Aleppo hospital had been killed.
Meanwhile, Swedish and Red Cross officials said two Swedish journalists abducted in Syria in November had been released. Sweden's Foreign Ministry confirmed the release of writer Magnus Falkehed and photographer Niclas Hammarstrom, and said both were receiving assistance from Swedish diplomats in Beirut. There were no further details on who abducted them or how they were set free.
As the rebel infighting continued, so did clashes between Assad's forces and rebels.
In Douma, a town close to the Syrian capital of Damascus, three people and a child were killed and several were wounded after a government airstrike targeted a house on Tuesday, reported the Observatory and another activist group, the Local Coordination Committees.
Dramatic footage of the aftermath of the strike was uploaded to social media networks. It corresponded with the Associated Press' reporting of the event.
"Be patient, little one, be patient!" a man is heard calling out in one video, shouting to a child heard wailing under the rubble of a smashed house. Minutes later, a toddler screams as he is seen being pulled out from the rubble. Another man is seen carrying a dust-covered, lifeless body of another child.