Security forces storm Syrian city of Aleppo, activist group says

(CNN) -- A Syrian city known for its relative calm during the Syrian uprising has been stormed by security forces, an opposition activist group said Tuesday.

The Local Coordination Committees of Syria -- a network of opposition activists -- said security and government forces entered the Tal Refaat neighborhood of Aleppo.

Aleppo, Syria's largest city, is the economic center of the country, and the city's merchant class had been largely unaffected by the country's upheaval.

Meanwhile, the city of Al-Rastan was being bombarded by the army and "heavy machine guns mounted on tanks," on Tuesday, the Syrian Observatory for Human Rights said.

The observatory said 20 people were wounded, seven of them seriously, in the Homs province city.

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Since protests began in March, demonstrators have demanded true democratic elections and the ouster of Syrian President Bashar al-Assad, but such protests have often been met with force.

Almost 3,000 people have died in the government's crackdown, according to some accounts. CNN is unable to independently confirm death tolls or events in Syria, which has restricted access to many parts of the country by international journalists.

The Syrian government has been battling opposition activists for what it calls a campaign against terrorists.

At the United Nations, Foreign Minister Walid Moallem blamed "foreign incitement" for the troubles, which he said were fueled by U.S. and European sanctions.

"This course cannot in any way be reconciled with pronouncements about concern for the interests, security and rights of the Syrian people," Moallem told the General Assembly. "It further runs counter to the basic principles of human rights in defense of which these states base their interference in our internal affairs."

He said Syria had been "a model of peaceful co-existence" among its people's religious and ethnic groups, and that disturbing that peace was aimed at "spreading Western hegemony over the countries of the Mediterranean and serving Israel's expansionist interests."

On Monday, the state-run news agency SANA published a report citing an unnamed military source saying that authorities found Israeli weapons, explosives and stolen military uniforms in Homs and recovered weapons, ammunition detonators and other military supplies hidden in a drum and a water tank in the garden of a house in Naseeb, a city in Daraa province.

CNN's Yousuf Basil contributed to this report.