ALEPPO, Syria —Syrian troops loyal to President Bashar al-Assad fought with rebels in the commercial hub of Aleppo after insurgents started what they said was a “decisive battle” to take the country’s largest city.

Syrian forces killed 22 “armed terrorists” and injured others in the Tal al-Zarazir neighborhood in the city of 3 million people, the state-run Syrian Arab News Agency reported today.

The main insurgent force in the city, the Tawheed Brigade, said on its Facebook page yesterday its fighters entered the Sheikh Maqsoud neighborhood. Bloomberg was unable to independently verify the legitimacy of the Facebook page.

International efforts to end the 18-month conflict have failed to stop the violence as rebels fight to overthrow Assad since March last year. The conflict has killed 30,000 people, according to estimates by the Syrian Observatory for Human Rights, an opposition group.

Fighting has been deadlocked in Aleppo since rebels pushed into the city in July. Government forces have resorted to heavy weaponry, including attack aircraft, helicopter gunships and artillery to dislodge rebels from their positions.

Government forces stormed several suburbs of the capital, Damascus, and pressed their attacks on other areas of the country, killing 25 today, the British-based observatory said in an e-mailed statement. Eighteen government soldiers were killed during fighting in Aleppo, Damascus, and Deir Ezzor, it said.

Conflict Expands

“This conflict continues to expand and deepen the humanitarian disaster,” Saudi Arabia’s Deputy Foreign Minister Prince Abdul Aziz bin Abdullah said yesterday during an address to the United Nations. “All that is happening amidst a noticeable international community’s failure due to the division in the Security Council.”

The U.N. Human Rights Council yesterday approved extending the mission of its independent commission of inquiry. An European Union statement called on Syrian authorities to “immediately put an end to the violence and condemned in the strongest terms the gross human-rights violations by the Syrian authorities which may amount to crimes against humanity.”

Defense Secretary Leon Panetta told a Washington news conference that intelligence suggests Assad’s government has moved some of its chemical weapons, although the United States believes the main sites remain secure, the Associated Press reported.

Panetta said he doesn’t have enough information to confirm if any of the moves suggest that some of the material has been acquired by rebels, AP reported.