Meanwhile, another kidnapping with a possible tie to the violence in Syria was reported in neighboring Lebanon, CNN reported.
At least 89 people were killed across Syria Thursday, including the 49 in Aleppo, the opposition Local Coordination Committees in Syria said.
Also Thursday, the Organization of Islamic Cooperation suspended Syria's membership, a move the United States said sends a strong message to President Bashar Assad.
The suspension came as the U.N. Security Council plans to meet to discuss the situation in Syria. The mandate for the U.N. observer mission in the country expires Sunday.
In a statement issued after the 57-member organization's action, U.S. State Department spokeswoman Victoria Nuland said the decision also demonstrates how Assad's government is becoming increasingly isolated internationally, Voice of America reported.
State-run media reported Thursday Syrian government forces had killed "terrorists" in Aleppo. Syrian leaders have called pro-democracy forces terrorists and thugs backed by foreign interests.
State-run television also reported Assad Thursday appointed Mohammed Wahid Aqaad as the new governor of Aleppo province.
CNN said mass protests and kidnappings have been reported in Lebanon between Syrians loyal to Sunni-dominated rebels and those backing Assad, an Alawite Muslim with Shiite support.
A Lebanese security official said a Syrian citizen, Houssam Khashroum, was kidnapped Thursday in front of a hospital in Zahle.
The unrest in Lebanon was sparked by the kidnapping of a Lebanese man, Hassan Salim Meqdad, in Damascus, Syria, by Syrian rebels who accused him of being a Hezbollah member. The rebel Free Syrian Army then distributed Meqdad's "confession" in which he said he was one of 1,500 Hezbollah militants operating in Syria, CNN said.
Saudi Arabia, Kuwait, Qatar and the United Arab Emirates have urged their citizens to leave Lebanon, citing deteriorating security.
The Assad regime also said Thursday its forces rescued three journalists being held in El Tal, north of Damascus, Syrian State TV reported. The three, who work for a pro-regime television station, were taken by rebels while covering the fighting in a suburb north of Damascus, State TV said.
The government's allegation came as the opposition group Syrian Observatory for Human Rights said reports indicated "a number of people were killed and injured" in El Tal after a raid by government forces.
The U.N. Independent International Commission of Inquiry found both sides committed war crimes in the conflict that began in March 2011, CNN reported Thursday. The U.N. panel, however, said the government's attacks, because of their scale, were crimes against humanity.
Human Rights Watch said Thursday a bombing of the rebel-controlled northern town of Azaz the previous day by a Syrian warplane killed more than 40 civilians and wounded 100. The group visited the site after the bombing, which the rights organization said destroyed an entire residential block and may have been targeting nearby facilities of the rebel Free Syrian Army.
Meanwhile, about 2.5 million Syrians face destitution as violence grows in populated areas, the top U.N. relief official said Thursday.
The United Nations estimates about 18,000 people have died since the fighting began. Opposition groups report a death toll as high as 22,000.
Meanwhile, Syrian envoy Bouthaina Shaaban praised China and Russia for their response to the crisis in Syria, saying they weren't acting like "colonizers."
China and Russia have vetoed three U.N. Security Council resolutions that would have sanctioned Syria for using heavy weapons against civilians.
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