BEIRUT (AP) -- Syrian rebels ousted an al-Qaida linked group from its local headquarters in a key northern city Wednesday, part of a widening campaign against the extremist group in opposition-held areas, activists said.
The capture of the base, formerly a children's hospital in Aleppo, underscores the intensity of the rebel-on-rebel fighting that has raged for days between moderate factions and their one-time allies, fighters from the Islamic State of Iraq and the Levant.
Meanwhile, two Swedish journalists who were abducted in Syria were released after a month and a half in captivity. Dozens of local and foreign journalists have been killed or kidnapped in Syria.
The Islamic State of Iraq and the Levant and another al-Qaida linked group known as Jabhat al-Nusra, or Nusra Front, initially joined forces with moderate rebels fighting to oust President Bashar Assad in a conflict that began in March 2011 as a popular uprising but morphed into a civil war. The extremists proved well-organized and efficient fighters, giving the ragtag rebels a boost. But the Iraqi-based network began employing brutal tactics and trying to impose its strict interpretation of Islamic law, alienating other factions and leading to some of the worst infighting of the conflict.
A spokesman for the Islamic State of Iraq and the Levant vowed to crush the rival rebel groups.
"Know that we have armies in Iraq and Syria ... we warn you," the spokesman, known as Abu Mohammed al-Adnani, said in an audio clip posted overnight on militant websites. "We will crush them and kill the conspiracy in its cradle," he said. The authenticity of the recording, which was posted on militant websites, could not be independently verified.
The spokesman also declared war against Shiites in Iraq, Syria, Lebanon and Yemen, whom Sunni Muslim extremists consider to be their main enemy.
The fighting has spread from the northern province of Aleppo to nearby Idlib and Raqqa, a bastion of the Islamic State of Iraq and the Levant. At least 300 people have been killed in the past five days, said Rami Abdurrahman, the head of the Britain-based Syrian Observatory for Human Rights.
The Observatory and other activists reported that dozens of detainees held by the extremists had been freed, but several others had been shot to death.
The Observatory said 42 bodies were found at the hospital, including five activists and at least 21 fighters. Other activist groups reported that dozens were executed, but the reports and numbers could not be immediately confirmed.
"We are very concerned about reports that the Islamic State is killing its detainees before pulling out from headquarters as they lose ground to rival armed groups," said Cilina Nasser, a Syria researcher with the human rights watchdog Amnesty International.
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-Qaida 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.
The Committee to Protect Journalists said that Syria was the most dangerous country in the world for journalists.
Swedish officials confirmed that writer Magnus Falkehed and photographer Niclas Hammarstrom were now free and said both were receiving assistance from Swedish diplomats in Beirut.
There were no further details on who abducted them or how they were freed, but Hammarstrom told a Swedish newspaper he had been shot in the leg during a failed escape attempt. Both freelancers were abducted on their way out of Syria in November.
Also Wednesday, the global chemical weapons watchdog urged Syria to intensify efforts to get its stockpile of raw materials for poison gas and nerve agents to a a port, so it can be shipped out of the country and destroyed.
The first batch of toxic chemicals -- believed to be precursors for mustard gas and sarin -- was loaded onto a Danish cargo ship in the Syrian port of Latakia and shipped toward international waters on Tuesday, a week after the Dec. 31 deadline initially set for the chemicals to be removed from Syria.
Associated Press writers Qassim Abdul-Zahra in Baghdad, Karl Ritter in Stockholm and Mike Corder in The Hague contributed to this report.
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