Combat operations in 2013 during the Battle of Aleppo

The al-Nusra Front unilaterally declared a no-fly zone in December and threatened to shoot down commercial aircraft, alleging that the government was using them to transport loyalist troops and military supplies.

By 12 January, army units had managed to gain control of the areas surrounding the historic Umayyad Mosque, the Citadel, and the Justice Palace near the Old City.

[8] However, by late February rebels had re-captured the mosque after days of heavy fighting, as government forces retreated to nearby buildings.

[17] On 29 January, the bodies of approximately 110 men and boys, most with bound hands and shot in the head were found on the banks of the Queiq River in the western district of Bustan al-Qasr, controlled by rebels.

[19] On 31 January, government warplanes bombed the Kurdish neighbourhood of Ashrafiyeh, controlled by the Popular Protection Units (YPG), killing at least twenty civilians and injuring 40.

Several days prior, on 28 January, a government tank reportedly fired a shell into the Kurdish sector of the city, killing one child and wounding two women.

[21] In early January 2013, rebels laid siege to the strategic Police Academy in Khan al-Assal on the western outskirts, which was used by the government to shell nearby areas.

[25] On 22 February, rebels alleged that three "Scud-type missiles" landed in the Hamra, Tariq al Bab and Hanano neighbourhoods with 29 confirmed dead and 150 wounded.

[31] During March, an eight-day rebel offensive in an attempt to capture the village of Khan al-Assal on the western outskirts of the city was repelled.

[33][34] On 15 March, rebels seized control of an ammunition factory complex and munitions depots in the town of Khan Tuman, southwest of Aleppo.

[43] On 2 April, clashes erupted in the strategic village of Aziza, on the southern outskirts, from which rebels were launching attacks against Aleppo international airport and the adjacent military air base.

The temporary truce allowed Red Crescent workers to remove 31 decomposing bodies killed in the poor al-Sakhour district located in northern Aleppo.

However, on 14 June, according to an opposition activist, the tide started reversing, after rebels halted an armoured reinforcement column from Aleppo headed for the two Shiite villages northwest of the city.

[72] During 13 June fighting in Aleppo city, government forces temporarily advanced into rebel-held Sakhour district from two directions, but were soon repelled.

[73] On 12 June, FSA fighters claimed to have killed 40 Hezbollah and Syrian army soldiers, who were traveling in buses, in an ambush between the villages of al-Bouz and al-Khanasir.

Aleppo military council leader Colonel Abdul Jabbar al-Oqaidi claimed, "The regime pushed forward in the north of the city, but the Free Syrian Army caused a lot of casualties and they went back to their bases.

[81] On 25 June, rebels advancing in western Aleppo were reportedly engaging in "tit for tat" operations against the Army in Rashidin and Ashrafiyeh, according to SOHR.

[83] Syrian government forces retained control over New Aleppo despite initial rebel advances in the area, with the opposing sides entrenched sometimes as close as 200 meters to one another.

[86] On 21 July, reports emerged that rebel fighters had taken full control of the Aleppo suburb of Khan al-Asal, along with the towns of Mataa and Summakiyah, east of the city.

[96] On 26 August, rebels took control of the strategic town of Khanasir located between Aleppo and Hama province reportedly killing more than 50 pro government fighters.

[98] On 21 September, rebels seized control of several villages south of Aleppo in an offensive aimed at cutting the supply lines of Pro Assad forces from Damascus.

A number of other militants were also killed in a separate incident during clashes with the Syrian army in the Ansari district, adjacent to Salah al-Din.

[102] State agency SANA claimed the Army had restored control over 40 villages in the area and engineering units had dismantled insurgent fortifications, about 600 anti-tank mines and 1,500 explosive devices.

According to Al-Jazeera, if the Army captured the base, it would cut the rebel supply routes between Aleppo city and the opposition-controlled town of al-Bab, about 30 kilometers from the Turkish border.

[118] On 12 November, government forces, backed by tanks, captured two highrise buildings in the northern Ashrafieh and Bani Zeid districts, and advanced into the two neighborhoods after close-quarter street fighting.

[121] In early December 2013, the Syrian Army launched operation Canopus Star with the aim to encircle Aleppo and cut rebel supply lines into the city, thus besieging rebel-held areas.

[122] Between 15 and 28 December 2013, a series of Army helicopter attacks with barrel bombs[123] against rebel-held areas of Aleppo left 517 people dead, including 151 children, 46 women and 46 rebels, according to the SOHR.

[126] On 20 December, Islamist rebels, including members of the Al-Nusra Front, took control over the Kindi hospital, which had been used by government soldiers as a base for several months.

[127][128] At least 20 regular soldiers were killed and dozens were taken prisoner in the fighting which began after two Al-Nusra fighters detonated themselves at checkpoints guarding the hospital.

[130] On 25 December, pro-government sources claimed that the Syrian Army captured the al-Sheikh Maqsoud and al-Jbanat areas of Aleppo city.