BEIRUT (AP) -- Syrian aircraft pummeled opposition areas in the northern city of Aleppo on Sunday, killing at least 32 people and extending the government's furious aerial bombardment of the rebel-held half of the divided city to an eighth consecutive day.
Since it began on Dec. 15, the government's unusually heavy air campaign in Aleppo has killed more than 200 people, smashed residential buildings and overwhelmed the city's hospitals with casualties. The timing of the assault -- a month ahead of planned peace talks in Switzerland -- suggests that Syrian President Bashar Assad could be trying to strengthen his position and expose the opposition's weaknesses before sitting down at the negotiating table.
Sunday's air raids targeted several Aleppo neighborhoods, but the worse hit was Masaken Hanano, where bombs fell on a second-hand market, a two-story building and a main road, activists said.
The Aleppo Media Center activist group said at least 32 people were killed, and published a list of the names of the dead on its Facebook page. Another group, the Britain-based Syrian Observatory for Human Rights, said in a later statement that at least 47 people, including seven rebels, were killed and dozens wounded.
"The medics say they are removing people in parts; they aren't sure how many there are," said Hassoun Abu Faisal, an activist with the Aleppo Media Center. He said the bombs destroyed vehicles lining a main road, destroyed a two-story building and left a crater where part of the market was.
Activists said the airstrikes were carried out by government helicopters that dropped so-called barrel bombs, crude devices filled with explosives and fuel that are wildly inaccurate but cause massive damage on impact.
Human rights groups warn that even if Syrian forces are targeting rebels with the bombs, they often explode in residential areas, killing civilians.
In an amateur video posted online, a man held up to the camera a severed foot from the air raids, while crowds scrambled among rubble, hoarsely shouting "God is Great!" as they came across corpses. Flames and dust from the smashed building and cars darkened the sky. One man rhythmically smashed a hammer against a jammed door of a vehicle containing charred bodies.
The videos appeared genuine and corresponded with other Associated Press reporting of the events depicted.
The air raids have exacted a devastating toll since they began. Over the first four days alone, the airstrikes killed at least 189 people and wounded 879, according to the aid group Doctors Without Borders.
Communities in the surrounding countryside have also been hit.
In the town of Marea north of Aleppo, a barrel bomb that exploded Sunday near a school used by Syrian fleeing fighting in other areas killed three members of the same family, according to Abu Faisal and the Observatory.
Schools decided to close Monday in opposition-held parts of Aleppo to avoid more casualties, citing the attacks in Marea, the Aleppo Media Center reported.
Syrian officials have not commented on the air raids in Aleppo, the country's largest city, and a major front in the war since the rebels launched an offensive there in mid-2012. The city has been carved into opposition- and government-held areas.
Syria's civil war, now into its third year, has killed more than 120,000 people, according to activists. Millions have fled their homes because of the fighting.
In central Syria, a suicide bomber blew himself up near a primary school in the predominantly Shiite town of Umm al-Amed in Homs province, killing at least 20 people, seven of them children, the Observatory said.
Syria's state news agency also put the death toll at 20, but said six children had died.
The bombing highlighted the sectarian overtones of the Syrian civil war, which is now in its third year.
Syria's rebels are mainly Sunni, with hard-line brigades emerging as the most powerful fighting groups. Shiites and other Syrian minority groups have either stayed neutral or sided with Assad, fearing for their future should the rebels prevail. Groups on both sides have targeted civilians.
Also Sunday, Syrian military aircraft bombed Bab al-Hawa, a border crossing to Turkey, said a private Turkish news agency, Dogan, and the Aleppo Media Center and the Local Coordinating Committees, two activist networks.
The news agency said the bombs hit the Syrian side of the crossing, killing or wounding several people, and that several ambulances from the Turkish town of Reyhanli were heading to the border gate to carry the wounded to hospitals. It was not immediately clear why the area was targeted.
Associated Press writers Albert Aji in Damascus, Syria, and Suzan Fraser in Ankara, Turkey, contributed to this report.
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